WO2021034858A1

WO2021034858A1 - Capillary blood collection using varying number of lancets

Info

Publication number: WO2021034858A1
Application number: PCT/US2020/046856
Authority: WO
Inventors: Michael Chen; Clarissa LUI; Habibullah Ahmad; Chelsea Gordon
Original assignee: Verily Life Sciences Llc
Priority date: 2019-08-22
Filing date: 2020-08-18
Publication date: 2021-02-25

Abstract

A blood extraction system can include a first lancet, a first lancet driver, a second lancet, a second lancet driver, and a blood collection vessel. A flow conduit network may extend from adjacent the first lancet and the second lancet and allow blood routing to the blood collection vessel. A sensor may be arranged to obtain information about an amount or rate of blood routed through the flow conduit network. A controller may cause the first lancet driver to drive the first lancet and receive from the sensor the information about the amount of blood routed through the flow conduit network. The controller may also cause the second lancet driver to drive the second lancet if the amount or rate of blood routed through the flow conduit network is below a threshold volume or rate after a threshold time.

Description

CAPILLARY BLOOD COLLECTION USING VARYING NUMBER OF

LANCETS

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority from and the benefit of U.S. Provisional Application No. 62/890,198, entitled “CAPILLARY BLOOD COLLECTION USING VARYING NUMBER OF LANCETS,” field August 22, 2019 (Attorney Docket No. 101146-1137874-376PV1), the full disclosure of which is incorporated herein by reference for all purposes.

TECHNICAL FIELD

[0002] The present disclosure generally relates to obtaining capillary blood, and more specifically, but not necessarily limited to, devices and methods that utilize lancets to facilitate capillary blood extraction and collection.

BACKGROUND

[0003] Collection of capillary blood is useful in a variety of circumstances. For example, relatively small amounts of blood obtainable through capillary blood collection can be used to test blood sugar levels or other characteristics that are useful for diagnosing conditions relevant to a patient and informing an appropriate course of treatment.

[0004] Typically, to collect capillary blood, the skin is pricked (e.g., with a lancet) to inflict a small wound. This allows a small amount of blood to exit through the wound from capillary blood vessels near the surface of the skin. The small size of the wound allows the healing process to begin quickly, such that the blood flow usually stops after a short interval. However, the wound site may be tender afterwards, leading to discomfort, especially if a large size of lancet is utilized in an effort to obtain a sufficiently large blood sample for conducting a particular analysis.

SUMMARY

[0005] Various examples of the present disclosure are directed to systems and methods for extraction of blood. For example, one disclosed method includes driving a first lancet from a housing containing a plurality of lancets to produce a first blood extraction wound. The method further includes monitoring, via a volumetric sensor, a volume of blood obtained from the first blood extraction wound to determine a first collected amount of blood. If the first collected amount of blood is below a first target threshold at a first predetermined elapsed time, the method can further include driving a second lancet from the plurality of lancets contained in the housing to produce a second blood extraction wound.

[0006] One disclosed system for extracting a prescribed volume of blood includes a lancet-driving system including one or more lancet drivers; a control circuit; a plurality of lancets, where each lancet in the plurality of lancets is individually addressable by the control circuit for driving by the lancet-driving system; a blood collection vessel including a storage cavity configured to receive blood from the subject; and a blood monitoring system including at least one volumetric sensor configured to detect volumetric flow of blood received in or directed toward the blood collection vessel. The control circuit is configured to cause the lancet-driving system to drive a first lancet of the plurality of lancets. The control circuit is also configured to cause the lancet-driving system to drive a second lancet of the plurality of lancets in response to an indication from the blood monitoring system that an amount of blood collected by a first threshold time after driving the first lancet is below a first threshold volume or rate.

[0007] One disclosed blood extraction device includes a device housing that at least partially contains: a first lancet; a first lancet driver; a second lancet; a second lancet driver; a blood collection vessel; a flow conduit network extending from adjacent the first lancet and the second lancet and by which blood is routable to the blood collection vessel; a sensor arranged to obtain information about an amount of blood routed through the flow conduit network; and a controller configured to: cause the first lancet driver to drive the first lancet; receive from the sensor the information about the amount of blood routed through the flow conduit network; and cause the second lancet driver to drive the second lancet if the amount of blood routed through the flow conduit network is below a threshold volume or rate after a threshold time. [0008] These illustrative examples are mentioned not to limit or define the scope of this disclosure, but rather to provide examples to aid understanding thereof. Illustrative examples are discussed in the Detailed Description, which provides further description. Advantages offered by various examples may be further understood by examining this specification. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate one or more certain examples and, together with the description of the example, serve to explain the principles and implementations of the certain examples.

[0010] FIG. 1 shows an example of a system for obtaining blood from a subject, according to certain examples of the present disclosure.

[0011] FIG. 2 shows an example of the system of FIG. 1 in a state after actuating a first lancet, according to certain examples of the present disclosure.

[0012] FIG. 3 illustrates an example of the system of FIG. 1 in a state after actuation of a second lancet, according to certain examples of the present disclosure. [0013] FIG. 4 illustrates an example of the system of FIG. 1 in a state following actuation of a third lancet and a fourth lancet, according to certain examples of the present disclosure.

[0014] FIG. 5 shows a flow chart that illustrates an example of a process that may be performed by the system of FIG. 1, according to certain examples of the present disclosure.

DETAILED DESCRIPTION

[0015] Examples are described herein in the context of systems for extracting and collecting blood. Those of ordinary skill in the art will realize that the following description is illustrative only and is not intended to be in any way limiting. Reference will now be made in detail to implementations of examples as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following description to refer to the same or like items.

[0016] In the interest of clarity, not all of the routine features of the examples described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer’s specific goals, such as compliance with application- and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. [0017] In an illustrative example, a person with a medical condition may need to provide a certain quantity of blood to facilitate a diagnosis. The person may use a device according to this disclosure to obtain the appropriate amount of blood. The device can be attached to the subject’s skin and create a seal before activating a first lancet to prick the skin and start blood flow for collection by the device. After a predetermined time, such as one minute into a four minute blood draw interval, if the amount of blood collected is detected by onboard sensors as not meeting a targeted collection rate, the device may trigger another lancet to prick the skin a second time. Pricking the skin the second time can increase the blood flow rate and increase the likelihood that an appropriate amount of blood will be obtained within the total time interval for collection. The device may have additional lancets that can each be activated individually if ongoing monitoring indicates that the amount of blood extracted has fallen behind a target rate. If enough blood is being obtained at a sufficient rate, the device may continue operation without utilizing the additional available lancets. In this fashion, the device may use only as many lancets as are needed to ensure a suitable amount of blood extraction within a particular amount of time and avoid unnecessary wounds or discomfort for the subject.

[0018] FIG. 1 shows an example system 103 for obtaining blood from a subject. The system 103 is shown with a device housing 107, which may include respective components of the system 103. Although the components in FIG. 1 are all shown within the device housing 107, in some examples, at least some components may be positioned at least partially outside of the device housing 107. Moreover in some examples, some components may be removable or replaceable, e.g., formed as cartridges or other consumable parts that may be installed prior to use and/or replaced upon use.

[0019] The system 103 includes a plurality of lancets 115. In FIG. 1, four lancets 115 A, 115B, 115C, and 115D are shown, although any suitable multiple number of lancets 115 may be included, including but not limited to two, three, four, or more than four.

[0020] The lancets 115 may be any suitable size or form factor for penetrating skin to release blood flow for collection by the system 103. For example, the lancets may correspond to needles with round cross-sections (e.g., such as may be common in 28 gauge or 27 gauge or other fine gauge needles on up through larger gauges such as 20 gauge), optionally with a beveled tip, or structures with a form factor like a blade (e.g., such as may be common in larger gauge lancets of 18 gauge, 17, gauge, or larger). Moreover, although the lancets 115 in FIG. 1 are all depicted as approximately the same size, a variety of sizes or form factors could be utilized in conjunction with one another.

[0021] The lancets 115 may be individually addressable. For example, the lancets 115 may be individually drivable, which may minimize a number of wounds that may be inflicted for obtaining a suitable quantity of blood during a blood draw procedure performed by the system 103.

[0022] The system may include a lancet housing 117. The lancet housing 117 may contain the lancets 115. The lancet housing 117 may include one or more projections 119 that may form a ring or other appropriate structure to form a seal on a subject's skin 123 during lancing. For example, the projections 119 may correspond to ridges or other structures that may generate a sealed volume 125 between the skin 123 of the subject and the lancet housing 117. The sealed volume 125 may provide an area in which blood released by blood extraction wounds 127 (FIGS. 2-4) imparted by operation of the lancets 115 may be collected and directed to a suitable location within the device housing 107 or associated structure.

[0023] A lancet driving system 133 may be included. The lancet driving system 133 may include one or more lancet drivers 135. The lancet driver 135 may include any suitable parts or components that can cause extension and/or retraction of the lancet 115 to produce a respective blood extraction wound 127. Suitable examples may include chemical charges (such as propellants activatable to generate pressure to push a piston or otherwise impart force for driving), springs, motors, or other force- imparting mechanisms.

[0024] In FIG. 1, the lancet driving system 133 is shown with four lancet drivers 135A, 135B, 135C, and 135D, e.g., each respectively coupled with a respective lancet 115 A, 115B, 115C, 115D. Although the lancet drivers 135 are shown in a one-to-one relationship with the respective lancets 115, other arrangements are possible. In some examples, a single lancet driver 135 may be capable of moving and/or cycling between different lancets 115 for respective actuations of the lancets 115.

[0025] A flow conduit network 143 is also shown in FIG. 1. The flow conduit network 143 may allow blood from lancet-imparted wounds to flow into the device. For example, the flow conduit network 143 can include any suitable number of conduits 145 or flow paths that may direct blood from a blood extraction wound 127 and into a blood collection vessel 147. The flow conduit network 143 may be part of or connected with the lancet housing 117 and/or may extend into the device housing 107. In some examples, the flow conduit network 143 may include portions or components sized for imparting particular microfluidic flow properties such as wicking, capillary action, or other flow properties or dynamics that may facilitate movement of blood through the system 103.

[0026] The flow conduit network 143 may include any suitable structure or architecture. For example, in FIG. 1, a respective flow conduit 145A, 145B, 145C, and 145D is shown for each respective lancet 115 A, 115B, 115C, and 115D.

However, other options may also be utilized. For example, a single conduit 145 may be arranged near multiple lancets 115, or a single conduit 145 may otherwise be able to receive blood from multiple wounds 127. In some examples, such as shown in FIG. 1, an aggregate conduit 145E may combine or otherwise channel blood received from individual conduits (e.g., from conduits 145A-D), although in some examples, individual conduits 145 may individually feed into the blood collection vessel 147 without combining first through an aggregate conduit 145E. Moreover, although FIG. 1 depicts a single blood collection vessel 147, more than one may be included, e.g., optionally each corresponding to different lancets 115.

[0027] The blood collection vessel 147 can include a storage cavity flowably connected (e.g., via the flow conduit network 143) to the lancet housing 117 (e.g., to a portion adjacent the sealed volume 125 formed by engagement of the subject’s skin 123 with the projection 119 or other part of the lancet housing 117). The blood collection vessel 147 may receive blood extracted from the subject through the skin 123 of the subject. The blood collection vessel 147 is shown in Figure 1 schematically within the device housing 107. However, the blood collection vessel 147 may be at least partially out of the housing, e.g., extending at least partially out or coupled via a hose or tube that extends out of the device housing 107. In some examples, the blood collection vessel 147 may be removable. For example, in use, the blood collection vessel 147 may correspond to a vial or other structure that may be removed upon filling to a suitable amount. In some examples, the blood collection vessel 147 may be coupled with or include appropriate gaskets or other sealing structures, for example, to facilitate removal of the blood collection vessel 147 without dripping or leaking of collected blood.

[0028] The system 103 also includes a control circuit 153. The control circuit may include appropriate components for controlling other parts of the system 103. For example, the control circuit 153 may be implemented such that each lancet 115 is individually addressable by the control circuit 153 for driving by the lancet driving system 133.

[0029] The control circuit 153 may include a controller 155. The controller 155 may be in communication with other components (e.g., denoted schematically by signal transmission marks 157 at the controller 155 and also at other components within the system 103 in FIG. 1). In some examples, the controller 155 may be capable of performing different functions including, but not limited to, keeping time, receiving inputs, making comparisons and/or determinations, and/or providing command signals to trigger operations or other acts of other components within the system 103.

[0030] The controller 155 may correspond to any suitable structure for enabling associated functions. In some examples, the controller 155 may correspond to an application-specific integrated circuit (ASIC) defined on a field-programmable gate array (“FPGA”) or other form of processor.

[0031] In FIG. 1, a user interface 175 is also shown. In use, the user interface 175 may provide input to the controller 155. For example, the user interface 175 may be or include a touch screen or button or other input mechanism. In some examples, the user interface 175 may allow a user (e.g., the subject or a clinician working with the subject) to input a command or otherwise control the system 103 to initiate operation of the system 103. In some examples, the user interface 175 may allow a user to adjust a target amount of blood to be collected, a total time interval to operate, a target subtotal amount of blood to be collected within a particular sub-interval, a duration or timestamp for an overall interval or sub-interval, and/or other operating parameters for the system 103.

[0032] The system 103 may further include a blood monitoring system 183, which may provide information about blood collected by the system 103. To this end, the blood monitoring system 183 may include any suitable form of sensors 185. In general, the sensors 185 may provide information for monitoring activity of the system 103 which may be used to facilitate determinations about subsequent actions of the system 103, such as whether driving additional lancets 115 may be warranted. [0033] In some examples, the sensors 185 may correspond to volumetric sensors, for example, which may provide information about a rate and/or amount of blood received by the system 103. Suitable examples may include, but are not limited to sensors that operate on optical, thermal, and/or conductive principles. As one illustrative example, an optical sensor at a particular location may detect a change in color or other light characteristic when blood reaches that location and so indicate that an amount of blood sufficient to reach that location has been obtained. Multiple optical sensors may be placed at different positions along a route to allow a variety of amounts to be detected. In some examples, fluid flow rate may be detected in a non- contact way and a total amount may be calculated based on flow rate detected and corresponding lengths of time for such flow rates. In some examples, a heating element may be provided upstream and a thermal sensor provided downstream to detect a resulting temperature that may be indicative of a corresponding flow rate. In some examples, conductive sensors may utilize electrodes placed at different locations along a channel. For example, when blood is occupying the space between a respective pair of electrodes, resistance measured between the electrodes may drop significantly and indicate that blood passing an upstream electrode reaches to a known location of a downstream electrode, which may allow a quantity and/or rate of collected blood to be identified.

[0034] The sensors 185 utilized may be any combination of different kinds of volumetric sensors. In some examples, different types of volumetric sensors may be utilized for redundancy purposes. Additionally, any suitable arrangement of the sensors 185 may be utilized. For example, although in FIG. 1 each respective sensor 185a, 185b, 185c, and 185d is shown on or adjacent to a respective conduit 145a,

145b, 145c, and 145d, the system 103 may additionally or alternatively include an aggregate sensor 185e that may provide information about an aggregated amount of blood. Moreover, an aggregate sensor 185e may be in any location. For example, although the aggregate sensor 185e is shown along a path leading into the collection vessel 147, the aggregate sensor 185e may gauge the vessel 147 itself alone or in combination with a portion of the flow conduit network 143 leading into the blood collection vessel 147. [0035] In some examples, the sensors 185 may additionally or alternatively include or correspond to other sensor types for detecting other characteristics other than flow rates or amounts. In some examples the sensors 185 may provide information about composition or other attributes of the blood, e.g., which may indicate whether additives may be warranted for introducing into the blood being collected by the system 103 or may be utilized for other purposes.

[0036] The system 103 may include one or more other components to facilitate functions of the system 103. For example, in FIG. 1, the system 103 is shown with a suction source 193. The suction source 193 may facilitate flow of received blood toward the blood collection vessel 147. The suction source 193 may correspond to a pump or a vacuum container capable of drawing a vacuum for moving or imparting flow in a particular direction of blood through the system 103. In some examples, the suction source 193 may correspond to a removable or replaceable component, for example, that may be capable of providing negative pressure for an individual blood extraction process or interval. In some examples, the suction source 193 may correspond to a syringe that can be pushed or pulled to generate negative pressure, e.g., prior to, concurrent with, or subsequent to driving any lancets 115.

[0037] In some examples, the system 103 may include one or more additive sources 197. The additive sources may provide additives to the collected blood. For example, the additive sources 197 may provide additive such as anticoagulants or markers. Anticoagulants may facilitate additional blood flow or prevent clotting of blood that might otherwise impede collection of blood by the device 103. Markers may be useful for tracking blood through testing or other purposes.

[0038] The additive source 197 may correspond to any suitable structure for providing additives to the collected blood. In some examples, the additive source may be a passive structure (such as a dried powder or compound that may be reconstituted upon contact with the liquid blood collected by the system 103). In some examples, the additive source 197 may be an active component, such as a nozzle with a controllable release mechanism that may be controlled in response to monitoring by input from sensors 185 and the controller 155.

[0039] As noted previously, various components of the system 103 may be replaceable or removably coupled relative to the device housing 107 and/or other components. For example, replaceable lancets 115 may allow different sizes of lancets 115 to be used and/or allow fresh lancets to be used in different blood extraction procedures. Replaceable components of the lancet housing 117, flow conduit network 143, and/or blood collection vessel 147 may avoid contamination between different blood extraction procedures. Replaceable components of the lancet driving system 133, the suction source 193, and/or additive sources 197 may allow lancet drivers 135 or other components to be recharged or replaced for subsequent operations. Replaceable sensors 185 may facilitate repairs or reconfiguring to detect other characteristics. In some examples, various components may be replaceable relative to the control circuit 153, which may allow the control circuit 153 to be re used and avoid costs of re-producing disposable versions of the control circuit 153. [0040] In some examples, elements in the device housing 107 may be remotely activated. For example, one or more components associated with the device housing 107 shown may receive a wireless command from a remote device, e.g., which may be any suitable device with a wireless transmitter, such as a smartphone, smartwatch, blood pressure sensor, continuous glucose monitor (“CGM”), etc. Such remote devices may be handheld or wearable devices or larger devices, such as one or more sensing systems as may be found in a hospital or other medical office or clinic. Suitable wireless communication mechanisms include Bluetooth®, Bluetooth® low- energy (“BLE”), WiFi, near-field communications (“NFC”), etc.

[0041] In operation, the system 103 may be utilized to control the number of lancets 115 utilized to collect an appropriate amount of blood. The system 103 may control the number of lancets 115 based on blood flow obtained by the system 103.

An example progression of states of the system 103 are shown in FIGS. 2-4. In particular, FIG. 2 shows an example of the system 103 in a state after actuating the first lancet 115a, FIG. 3 illustrates the system 103 in a state after actuation of a second lancet 115b, and FIG. 4 illustrates the system 103 a state following actuation of a third lancet 115c, and fourth lancet 115d.

[0042] Referring to FIG. 2, the system 103 may drive the first lancet 115a and create a first blood extraction wound 127a. For example, the controller 155 may provide a command signal to the first lancet driver 135a, which may drive the first lancet 115a.

[0043] The resulting wound 127a may allow blood 129 to begin flowing toward the blood collection vessel 147. The projections 119 of the lancet housing 117 may provide a seal that prevents leakage of the blood 129 out of the sealed volume 125 and outside of the lancet housing 117. The blood 129 may be directed toward the blood collection vessel 147, for example, through the flow conduit network 143 and under effect of the suction source 193.

[0044] The received blood 129 can pass the sensor 185a to allow for monitoring of the blood flow in the system 103. For example, in FIG. 2, the blood 129 may pass the sensor 185a and a subsequent sensor 185e en route to the blood collection vessel 147. The received blood 129 may also receive additives en route, for example, from the first additive source 197a.

[0045] The controller 155 may monitor an amount of blood collected in the blood collection vessel 147 or a rate of blood flowing through the system 103, e.g., based on input from the sensors 185. The controller 155 may track blood flow rate and/or blood collection amounts over time and use such information for determinations about subsequent actions to trigger.

[0046] Referring to FIG. 3, after a first elapsed time, the controller 155 may determine that a collected amount of blood 129 in the blood collection vessel 147 or directed toward the blood collection vessel 147 may be less than a first target threshold for a first predetermined elapsed time. This may warrant using an additional lancet to make an additional wound for increased blood flow or amount. For example, with the seal maintained by the projections 119 of the lancet housing 117, the second lancet 115b may be driven by the second lancet driver 135b in response to a signal sent by the controller 155.

[0047] In some examples, the second lancet 115b may be larger than the first lancet 115a, e.g., which may increase a likelihood of the adequate amounts of blood 129 being obtained. In some examples, the second lancet 115b may be of a similar size to the first lancet 115a (e.g., increasing the number of wounds may be sufficient to obtain adequate amounts of blood even if wound size is not varied).

[0048] Blood from the second wound 127b may be directed toward the blood collection vessel 147, for example, to supplement the flow of blood 129 from the first wound 127a (e.g., if the first blood extraction wound 127a is still allowing blood to flow) or to replace blood flow (e.g., if the first blood extraction wound 127a has stopped permitting blood flow therethrough). The blood 129 passing through the system 103 (e.g., through the second flow conduit 145b) may pass through or be monitored by the blood monitoring system 183 (such as by the second sensor 185b with the second flow conduit 145b and/or the aggregate sensor 185e that is determining an aggregate amount of blood 129).

[0049] Referring to FIG. 4, after a further elapsed time, the controller 155 may again evaluate the monitored blood flow relative to a target value. For example, the controller 155 may determine that the collected amount of blood 129 is less than a second target threshold for a second predetermined elapsed time. This may warrant one or more additional lancets 115 to make one or more additional blood extraction wounds 127 and increase blood flow available to the system 103. This may correspond to triggering the third lancet 115 through the third lancet driver 135c, for example.

[0050] In some examples, additional elapsed time and monitoring may occur between driving the third lancet 115c and driving a fourth lancet 115d or other subsequent lancet. In some examples, lancets 115 are triggered in tandem. This may correspond, e.g., to both of the lancets 115c and 115d being fired simultaneously or otherwise based on the same threshold. For example, even if not fired simultaneously, a set of lancets 115 may be fired sequentially, e.g., one right after the other without a separate monitoring or responding to a different threshold in between.

[0051] Once again, the projections 119 may provide a seal or maintain a seal previously established and prevent leakage from the lancet housing 117. Blood flowing in through the system 103 may be detected or monitored by the blood monitoring system 183 (such as the third sensor 185c, the fourth sensor 185d, and/or the aggregate sensor 185e).

[0052] When a target threshold is reached, the system 103 may deactivate. For example, the controller 155 may determine based on input from the sensors 185 that a suitable amount of blood collection has been achieved. In response, the controller 155 may deactivate the suction source 193 or otherwise trigger other actions to facilitate sealing of the blood collection vessel 147 or other end states of the system 103. It is to be noted that the end condition or termination of operation of the system 103 may occur without driving all of the lancets 115. For example, if targets at elapsed times are reached, the system 103 may continue without triggering driving of additional lancets 115. Hence, the system 103 may allow a minimal number of lancets 115 to be used. This may correspond to a less invasive or less traumatic blood extraction process than if all of the lancets 115 were activated together and/or if larger lancets were used. In some examples, the blood collection vessel 147, after conclusion of the blood extraction process, may be removed and/or any other parts may be replaced to facilitate a subsequent blood extraction process.

[0053] FIG. 5 shows a flow chart that illustrates a process 500 that may be performed by the system 103. At 510, the process 500 may include receiving input. For example, this may correspond to receiving input via the user interface 175. In some examples, the input received at 510 may correspond to input obtained from a stored value that a user need not adjust or input.

[0054] The input received at 510 may include a target amount of blood to be collected by the system during a blood extraction process. In some examples, the input received at 510 may correspond to certain time thresholds at which target amounts are to be evaluated. In some examples, the input received at 510 may correspond to target amounts to be evaluated at respective time thresholds. For example, the operation at 510 may allow a user to adjust an amount and/or time mark for adjusting the goals to be achieved by the system 103 and/or other parameters that may be used for determining if or when to drive additional lancets 115 during the process.

[0055] At 520, the process 500 may include receiving a control signal. For example, the control signal may include a signal to start the blood extraction process. The control signal at 520 may correspond to the control signal received via the user interface or a remote device.

[0056] At 530, the process 500 could include triggering the driving of a first lancet 115a. This may correspond to the controller 155 sending a signal to the first lancet driver 135a. Driving the first lancet 115 may generate a first blood collection wound 127a.

[0057] In some examples, the process 500 may additionally include sealing prior to or in conjunction with triggering the driving of a first lancet 115a at 530. For example, the projections 119 of the lancet housing 117 may form a suitable seal against the skin 123 of the subject.

[0058] At 540, the process may include causing blood to be directed toward blood collection vessel 147. For example, this may be facilitated by operation of the suction source 193. In some examples at 540, the blood may be directed toward a vessel outside of the device housing 107.

[0059] At 550, the method can include monitoring. For example, this may include the controller 155 obtaining information from the blood monitoring system 183 and/or the sensors 185. The monitoring at 550 may correspond to monitoring an amount or a flow rate of blood received by the system 103. The monitoring at 550 may additionally or alternatively include determining other characteristics of the blood. [0060] At 560, the process can include causing additives to be introduced. For example, this may correspond to operation of one or more additive sources 197a-d. In some examples, this may correspond to the controller 155 providing a signal to cause the additive source 197 to add the additive to the received blood. In some examples, the additives introduced at 560 are based on information obtained from monitoring at 550. In some examples, the additives introduced at 560 are introduced passively, e.g., without action by the controller 155.

[0061] At 570, a determination may be made regarding whether a target total amount of blood has been reached. For example, this may correspond to the controller 155 determining whether the blood collection vessel 147 has received a predetermined amount. For example, the predetermined amount may have been input through the user interface at 510 as a predetermined amount to be obtained through the blood extraction process. If the target total amount has been reached (yes at 570), the process may terminate as having completed the necessary blood extraction. For example, the controller 155 may terminate the suction source 193 operation or otherwise cease operation of other components.

[0062] If the target total amount has not been reached at 570 (no at 570), the process may continue at 580. At 580, an elapsed time threshold may be reached. For example, this may correspond to a time threshold input at 510. Once the elapsed time threshold has been reached at 580, the process may continue at 590.

[0063] At 590, a determination may be made of whether a collected amount is below a target threshold or milestone for the elapsed time threshold. For example, this may correspond to the controller 155 determining that a flow rate or amount of collected blood is below a milestone for the elapsed time. If the collected amount is at or above the target threshold or milestone (no at 590), the process may proceed without triggering an additional lancet, for example resuming at 540 or other earlier stage in the process 500 to allow the process 500 to continue through subsequent stages. If the milestone is not met, (yes at 580), the process may continue at 595. [0064] At 595, the controller 155 may cause an additional lancet to be driven. Following driving of the additional lancet, the process may resume at 540 and continue through subsequent stages in the process. For example, blood released by driving the subsequent lancet at 595 may be directed toward the collection vessel at 540 and monitored at 550 in a manner that facilitates subsequent determinations at 570 and/or 590. The subsequent determinations at 570 and/or 590 may correspond ultimately to an iterative process of determining that either a collected amount of blood is sufficient and operation can cease (e.g., yes at 570) or that additional blood is needed and an additional lancet should be fired (e.g., yes at 590). In some examples, an additional determination may be made prior to 590 to determine if additional lancets are available, for example, to direct the process toward the end state instead of toward driving an additional lancet at 595.

[0065] The foregoing description of some examples has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Numerous modifications and adaptations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the disclosure. For example, more or fewer steps of the processes described herein may be performed according to the present disclosure. Moreover, other structures may perform one or more steps of the processes described herein.

[0066] Reference herein to an example or implementation means that a particular feature, structure, operation, or other characteristic described in connection with the example may be included in at least one implementation of the disclosure. The disclosure is not restricted to the particular examples or implementations described as such. The appearance of the phrases “in one example,” “in an example,” “in one implementation,” or “in an implementation,” or variations of the same in various places in the specification does not necessarily refer to the same example or implementation. Any particular feature, structure, operation, or other characteristic described in this specification in relation to one example or implementation may be combined with other features, structures, operations, or other characteristics described in respect of any other example or implementation. [0067] Some examples in this disclosure may include a processor. A computer- readable medium, such as RAM may be coupled to the processor. The processor can execute computer-executable program instructions stored in memory, such as executing one or more computer programs. Such processors may comprise a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), field programmable gate arrays (FPGAs), and state machines. Such processors may further comprise programmable electronic devices, such as programmable logic controllers (PLCs), programmable interrupt controllers (PICs), programmable logic devices (PLDs), programmable read-only memories (PROMs), electronically programmable read-only memories (EPROMs or EEPROMs), or other similar devices.

[0068] Such processors may comprise, or may be in communication with, media, for example, computer-readable storage media, that may store instructions that, when executed by the processor, can cause the processor to perform the steps described herein as carried out, or assisted, by a processor. Examples of computer-readable media may include, but are not limited to a memory chip, ROM, RAM, ASIC, or any other medium from which a computer processor can read or write information. The processor, and the processing described, may be in one or more structures, and may be dispersed through one or more structures. The processor may comprise code for carrying out one or more of the methods (or parts of methods) described herein. [0069] Use herein of the word “or” is intended to cover inclusive and exclusive “or” conditions. In other words, A or B or C includes any or all of the following alternative combinations as appropriate for a particular usage: A alone; B alone; C alone; A and B only; A and C only; B and C only; and all three of A and B and C.

Claims

CLAIMS That which is claimed is:

1. A system for extracting a prescribed volume of blood from a subject, comprising: a lancet-driving system comprising one or more lancet drivers; a control circuit; a plurality of lancets, wherein each lancet in the plurality of lancets is individually addressable by the control circuit for driving by the lancet-driving system; a blood collection vessel comprising a storage cavity configured to receive blood from the subject; and a blood monitoring system comprising at least one volumetric sensor configured to detect volumetric flow of blood received in or directed toward the blood collection vessel; wherein the control circuit is configured to: cause the lancet-driving system to drive a first lancet of the plurality of lancets; and cause the lancet-driving system to drive a second lancet of the plurality of lancets in response to an indication from the blood monitoring system that an amount of blood collected by a first threshold time after driving the first lancet is below a first threshold volume or rate.

2. The system of claim 1, further comprising a lancet housing configured to form a seal on a subject’s skin during lancing, wherein the storage cavity is flowably connected to the lancet housing.

3. The system of claim 2, further comprising a device housing, configured to house the lancet-driving system, the control circuit, the plurality of lancets, the lancet housing, and the blood collection vessel.

4. The system of claim 3, wherein the blood collection vessel is removably installed in the device housing.

5. The system of claim 1, further comprising a user interface configured to accept user input regarding the prescribed volume of blood.

6. The system of claim 1, further comprising a user interface configured to accept user input regarding the first threshold time.

7. The system of claim 1, further comprising a user interface configured to accept user input regarding the first threshold volume or rate.

8. The system of claim 1, further comprising a suction source configured to facilitate flow of received blood toward the blood collection vessel.

9. The system of claim 1, wherein the lancet-driving system comprises a propellant activatable to drive at least one of the lancets.

10. The system of claim 1, further comprising an additive source arranged to introduce an additive into the blood received from the subject.

11. The system of claim 10, wherein the additive is an anticoagulant.

12. The system of claim 10, wherein the additive source comprises a dried compound configured to reconstitute upon contact with the received blood.

13. The system of claim 1, wherein the at least one volumetric sensor of the blood monitoring system comprises at least one of an optical sensor, a thermal sensor, or a conductive sensor.

14. A blood extraction device comprising a device housing that at least partially contains: a first lancet; a first lancet driver; a second lancet; a second lancet driver; a blood collection vessel; a flow conduit network extending from adjacent the first lancet and the second lancet and by which blood is routable to the blood collection vessel; a sensor arranged to obtain information about an amount of blood routed through the flow conduit network; and a controller configured to: cause the first lancet driver to drive the first lancet; receive from the sensor the information about the amount of blood routed through the flow conduit network; and cause the second lancet driver to drive the second lancet if the amount of blood routed through the flow conduit network is below a threshold volume or rate after a threshold time.

15. A method compri sing : driving a first lancet from a housing containing a plurality of lancets to produce a first blood extraction wound; monitoring, via a volumetric sensor, a volume of blood obtained from the first blood extraction wound to determine a first collected amount of blood; and if the first collected amount of blood is below a first target threshold at a first predetermined elapsed time, driving a second lancet from the plurality of lancets contained in the housing to produce a second blood extraction wound.

16. The method of claim 15, further comprising: forming a seal about an area of skin, wherein the first blood extraction wound is produced within the area and the second blood extraction wound is produced within the area.

17. The method of claim 16, further comprising: collecting blood from the first blood extraction wound and the second blood extraction wound while the seal is maintained.

18. The method of claim 15, further comprising: collecting blood from the first blood extraction wound and the second blood extraction wound into a blood collection vessel contained within the housing.

19. The method of claim 15, further comprising: after driving the second lancet, monitoring a volume of blood obtained to determine a second collected amount of blood; and if the second collected amount of blood is below a second target threshold at a second predetermined elapsed time, driving one or more further lancets from the plurality of lancets contained in the housing to produce one or more further blood extraction wounds.

20. The method of claim 19, wherein the driving one or more further lancets comprises: driving a third lancet from the plurality of lancets contained in the housing to produce a third blood extraction wound; after driving the third lancet, monitoring a volume of blood obtained to determine a third collected amount of blood; and if the third collected amount of blood is below a third target threshold at a third predetermined elapsed time, driving a fourth lancet from the plurality of lancets contained in the housing to produce a fourth blood extraction wound.

21. The method of claim 19, wherein the driving one or more further lancets comprises driving a third lancet and a fourth lancet from the plurality of lancets in tandem.