GB2540197A

GB2540197A - Blood sample collection apparatus

Info

Publication number: GB2540197A
Application number: GB1512032.2A
Authority: GB
Inventors: Wreford Bill
Original assignee: COUNTY PATHOLOGY Ltd
Current assignee: COUNTY PATHOLOGY Ltd
Priority date: 2015-07-09
Filing date: 2015-07-09
Publication date: 2017-01-11
Also published as: GB201512032D0

Abstract

An apparatus for aiding the collection of a blood sample from a finger 14 has an elastic band 6 configured to be placed over a subjects digit to restrict venous flow and/or capillary blood, but not to restrict arterial blood flow, such that blood flows out of the digit when pricked. The band may be rubber and free from latex, with a diameter of 14-16mm, length of 24-26 mm, width of 0.5-2.5mm and thickness of 0.5-2.5 mm, such as a number 7 elastic band. It may have a square, circular or oval cross-section and it may be coated in talc. The apparatus may include a lancet 4, needle or pin for puncturing the finger and a vial (8, figure 5), funnel or capillary tube for collecting the blood sample (18, figure 5).

Description

BLOOD SAMPn: COLLECTION APPARATUS

The invention relates to blood sample collection apparatuses, and particularly, although not exclusively to capillary blood sample collection apparatuses, and to methods for collecting capillary blood samples. The invention relates to self testing kits, and methods for taking blood samples at home, as well as to taking samples in a hospital or doctor’s surgery, a clinic, or a pharmacy.

Capillary blood sampling is a common technique used to take a small volume of a patient’s blood for subsequent diagnostic testing in a laboratory. The blood sample is taken by puncturing the skin, usually on the finger but can be elsewhere on the body, and allowing a small volume to flow into a vial or similar container or directly into an analyser. A doctor or nurse may perform the procedure, if the patient is in hospital or a clinic. However, in recent years, there has been a considerable move to allowing patients to collect their own blood sample themselves, which they then send to a diagnostic company which performs the analysis. A problem with existing capillary blood sample collection kits is that they suffer from a very high failure rate (at least 20-30%), because users do not collect enough good quality blood in the vial for the diagnostic company to be able to carry out the testing.

There is therefore a need for improved apparatus and methods for taking capillary blood samples, especially at home.

Accordingly, in a first aspect of the invention, there is provided a blood sample collection apparatus comprising a band configured to be placed over a subject’s digit to restrict venous flow and/or capillary blood therein, but not restrict arterial blood flow, such that blood flows out of the digit, when pricked.

Advantageously, the dimensions and elasticity of the band in the apparatus of the invention are such that the optimum pressure is applied around the digit, which is sufficient to restrict venous and capillary blood flow therein (i.e. blood flowing through the veins and capillaries in the digit), but allow arterial blood flow therein (i.e. blood flowing through the arteries in the digit), such that a suitable volume of blood flows out of the digit, when it is pricked. Accordingly, a good blood flow is achieved out of the pricked digit, such that reasonable sample sizes can be quickly and conveniently collected.

Preferably, the apparatus is a capillary blood sample collection apparatus.

The apparatus of the first aspect solves the high failure rate problem associated with prior art capillary blood sample collection kits, because users of the invention are able to collect enough blood for diagnostic companies to be able to carry out their tests. The digital band is distinguished from a digital tourniquet which restricts both arterial and venous/capillary flow, and so suffers from poor blood flow and smaller samples or extended sample times.

The blood sample collection apparatus of the invention may be used to collect blood samples in a hospital, clinic or laboratory. Preferably, however, the apparatus is used at home, i.e. for home or self blood sample collection.

Preferably, the band is elastic. The band preferably comprises or consists of rubber. The rubber maybe synthetic rubber, but is preferably natural rubber. Preferably, the band does not contain any latex. Thus, advantageously, it does not cause any allergic reactions when contacting the subject’s skin on the digit.

The Young’s Modulus of the band under a small strain is preferably 0.01-0.1 GPa.

The band is preferably a number 7 size elastic band. The diameter of the band when substantially circular may be between 10mm and 20mm, preferably between 12mm and 18mm, and more preferably between 14mm and 16mm. The length of the band when substantially flattened may be between 20mm and 30mm, preferably between 22mm and 28mm, and more preferably between 24mm and 26mm. The width of the band may be between 0.5mm and 2.5mm. The thickness of the band maybe between 0.5mm and 2.5mm.

In one embodiment, the band has a substantially square cross-section. However, for some patients, especially men with hairy fingers, the embodiment with a square cross-section can trap the hairs when rolling the band up and down the finger. Accordingly, in a preferred embodiment, the band has a smooth or curved cross-section section. Most preferably, the band has a substantially circular or oval cross-section.

The mean diameter of a cross-section of the band may be between 0.5mm and 2.5mm. This embodiment with a smooth surface is preferred as it is more comfortable because there is less tendency to trap hairs when rolling the band up and down the digit.

The band preferably comprises a coating of a material which reduces friction with the patient’s skin and improves comfort. For example, a preferred material is talc powder. Advantageously, the talc improves the application of the band to, and removal of the band from, the patient.

The apparatus preferably comprises pricking means for producing the prick in the subject’s digit through which blood may flow. Preferably, the pricking means is configured to produce the prick at or towards the tip of the digit. For example, the pricking means may comprise a lancet, a needle or a pin, or the like.

Preferably, the apparatus comprises means for collecting the blood sample which flows out of the prick in the subject’s digit. The blood collection means may comprise a vial, funnel, capillary or a similar collection device. The collection means may comprise a removable lid.

Accordingly, preferably the apparatus of the invention comprises a kit of parts for collecting a blood sample from a subject, the kit comprising the band, the pricking means and the blood collection means.

In a second aspect of the invention, there is provided use of a band for collecting a blood sample from a subject, wherein the band is configured to be placed over a subject’s digit to restrict venous flow and/or capillary blood therein, but not restrict arterial blood flow.

In a third aspect of the invention, there is provided a method for collecting a blood sample from a subject, the method comprising placing a band over a subject’s digit, wherein the band restricts venous flow and/or capillary blood in the digit, but not arterial blood flow, and pricking the digit such that blood flows therefrom.

The band may be applied onto any digit, for example a finger or a toe. In one preferred embodiment, the band is placed over the index finger, thumb, middle, ring or little finger. However, the index finger is preferred. In another preferred embodiment, the band is placed over the hallux, long, third, fourth of fifth toe. Preferably, the band is positioned at or towards the top of the digit, i.e. where fingers are attached to the palm of the hand, or where toes are attached to the main part of the foot.

The method preferably comprises rolling the band along the digit towards the position of the prick, thereby increasing blood pressure in the digit, most preferably prior to pricking the digit. Preferably, the method comprises rolling the band along the digit to the first knuckle on the digit. The inventor has found that the first knuckle is the preferred position for the band for providing the optimum internal pressure to achieve a good blood flow out of the prick, but other positions on the digit still work. Preferably, the method comprises pricking the digit with pricking means, for example a lancet, needle or pin.

The dimensions and tension of the band, which is preferably elastic, are such that pressure is applied around the digit, which is sufficient to restrict venous and capillary blood flow therein, but allow arterial blood flow therethrough. Accordingly, blood flows freely out of the prick. The method preferably comprises collecting the blood in a blood collection means, which may be a vial. Once sufficient blood has been collected, the method comprises sealing the vial. The method may then comprise rolling the band off the digit, thereby reducing the blood pressure, such that blood flow reduces and eventually stops. The prick may be covered with an aseptic plaster to prevent infection. The method comprises sending the collection means containing the blood sample for diagnostic testing. The pricking means and band may then be disposed of.

All of the features described herein (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, maybe combined with any of the above aspects in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying Figures, in which:-

Figure 1 is a schematic side view of one embodiment of a blood sample collection apparatus or kit of the invention. The kit includes a lancet, an elastic band and a collection vial;

Figure 2 shows a cross-sectional view of a first embodiment of the elastic band; Figure 3 shows a cross-sectional view of a second embodiment of the elastic band;

Figure 4 shows a view of the kit in use on a patient, with the band in a first position on the patient’s finger; and

Figure 5 shows a view of the kit in use on the patient, with the band in a second position on the patient’s finger.

Referring to Figure 1, there is shown a blood sample kit 2 for taking capillary blood samples from a patient. The kit can be used to collect blood samples in a hospital, clinic or lab, but is intended to be used primarily at home for home sampling. The kit 2 consists of a lancet 4, an elastic band 6 and a collection vial 8 having a threaded lid 10 removeably attached thereto.

Referring to Figure 2, one embodiment of the band 6 has a square cross-section. However, as shown in Figure 3, a second embodiment of the band 6 has a smooth or circular cross-section, and resembles an O-ring. The band is made of rubber (synthetic or natural), and ideally, is latex free. The Young’s Modulus of rubber under a small strain is 0.01-0.1 GPa. The band 6 is also covered in a thin coating of talc powder which improves its application to, and removal from, the patient. The band is a No. 7 elastic band having the following dimensions: diameter when circular: 15mm; length when flattened: 25mm; width: 1.5 mm; thickness: 1.5mm.

Figures 4 and 5 show the kit 2 in use on a patient’s hand. First, the band 6 is applied onto the patient’s digit, for example the index finger 14, and then moved up until it is at the top of the finger, as shown in Figure 4. It will be appreciated that any digit could be used, for example the thumb, middle, ring or little finger, but usually the index finger is preferred. Similarly, the kit 2 could also be used with the patient’s toes, for example the hallux, long, third, fourth of fifth toe. Next, the band 6 is then rolled down to the first knuckle 16 on the pricked finger 14, as shown in Figure 5. The dimensions and tension of the band are such that pressure is applied around the finger, which is sufficient to restrict venous and capillary blood flow therein, but allow arterial blood flow therethrough.

Next, the lancet 4 is provided as a means for producing a prick 12 on the end of the patient’s finger 14 with the band 6 positioned at the first knuckle. It will be appreciated that the lancet 4 can be either manual or require the user to press a button to create the prick. It is conceivable that a needle or pin could also be used instead of a lancet 4 to create the puncture 12 in the finger 14.

Accordingly, blood 18 flows freely out of the prick 12, and is collected in the vial 8, as shown. Once sufficient blood 18 has been collected, the lid 10 is screwed onto the top of the vial 8, and the band 6 is rolled completely off the finger 14, thereby reducing the pressure, such that blood flow stops. The prick 12 can be covered with an aseptic wipe to prevent infection. The vial 8 containing a sufficient volume of blood 18 is then sent off to the diagnostic company for testing. The needle 4 and band 6 can then be disposed of.

Advantages of the apparatus 2 of the invention reside in the provision of the band 6, which is of sufficient elasticity to effectively restrict venous and capillary blood flow, but allow arterial blood flow. This means that the optimum pressure of blood is achieved within the finger and so a good flow of blood out of the prick 12 is possible, meaning good sample sizes maybe quickly and conveniently collected. The band 6 is distinguished from a tourniquet which restricts both arterial and venous flow, thereby resulting in poor or insufficient blood flow. In its simplest form, the band 6 can be a normal elastic band (e.g. No. 7) having the square cross-section shown in Figure 2. However, for some patients, especially men with hairy fingers, the embodiment with a smooth surface (i.e. a circular cross-section) shown in Figure 3 is preferred as it is more comfortable because there is less tendency to trap the hairs when rolling the band up and down the finger 14. Provision of talc further reduces friction with the patient’s skin and improves comfort. Finally, the band can be disposable and so is cheap to manufacture.

Claims

1. A blood sample collection apparatus comprising a band configured to be placed over a subject’s digit to restrict venous flow and/or capillary blood therein, but not restrict arterial blood flow, such that blood flows out of the digit, when pricked.

2. An apparatus according to claim l, wherein the apparatus is a capillary blood sample collection apparatus.

3. An apparatus according to either claim 1 or claim 2, wherein the blood sample collection apparatus is used to collect blood samples in a hospital, clinic, laboratory, or at home.

4. An apparatus according to any preceding claim, wherein the band is elastic.

5. An apparatus according to any preceding claim, wherein the band comprises or consists of rubber.

6. An apparatus according to any preceding claim, wherein the band does not contain any latex.

7. An apparatus according to any preceding claim, wherein the diameter of the band when substantially circular is between 10mm and 20mm, or between 12mm and 18mm, or between 14mm and 16mm.

8. An apparatus according to any preceding claim, wherein the length of the band when substantially flattened is between 20mm and 30mm, or between 22mm and 28mm, or between 24mm and 26mm.

9. An apparatus according to any preceding claim, wherein the width of the band is between 0.5mm and 2.5mm.

10. An apparatus according to any preceding claim, wherein the thickness of the band is between 0.5mm and 2.5mm.

11. An apparatus according to any preceding claim, wherein the band has a substantially square cross-section.

12. An apparatus according to any preceding claim, wherein the band has a smooth or curved cross-section section.

13. An apparatus according to any preceding claim, wherein the band has a substantially circular or oval cross-section.

14. An apparatus according to claim 13, wherein the mean diameter of a cross-section of the band is between 0.5mm and 2.5mm.

15. An apparatus according to any preceding claim, wherein the band comprises a coating of a material which reduces friction with the patient’s skin and improves comfort.

16. An apparatus according to claim 15, wherein the material is talc powder.

17. An apparatus according to any preceding claim, wherein the apparatus comprises pricking means for producing the prick in the subject’s digit through which blood may flow.

18. An apparatus according to claim 17, wherein the pricking means comprises a lancet, a needle or a pin, or the like.

19. An apparatus according to any preceding claim, wherein the apparatus comprises means for collecting the blood sample which flows out of the prick in the subject’s digit.

20. An apparatus according to claim 19, wherein the blood collection means comprises a vial, funnel, capillary or a similar collection device.

21. An apparatus according to any preceding claim, wherein the apparatus comprises a kit of parts for collecting a blood sample from a subject, the kit comprising the band, pricking means and blood collection means.

22. Use of a band for collecting a blood sample from a subject, wherein the band is configured to be placed over a subject’s digit to restrict venous flow and/or capillary blood therein, but not restrict arterial blood flow.