WO2013045695A2

WO2013045695A2 - Method for delivering a sample of body fluid to an analysing system, a syringe designed for use therein and a kit comprising such a syringe

Info

Publication number: WO2013045695A2
Application number: PCT/EP2012/069341
Authority: WO
Inventors: Adam WARCHUSKI; Piotr Garstecki; Marcin Izydorzak; Pawel MICHALAK; Kamil PRUSAK
Original assignee: Pz Cormay S.A.
Priority date: 2011-09-30
Filing date: 2012-10-01
Publication date: 2013-04-04
Also published as: WO2013045695A3

Abstract

A method for delivering a sample of body fluid to an analysing system, comprising the steps: a) collecting the body fluid in a reservoir of a storage element, b) centrifuging the body fluid in the reservoir of the storage element, characterised in that subsequently c) the body fluid is pushed out from the reservoir (4, 24) of the storage element to the analysing system. The invention comprises also a syringe intended for use in such a method for delivering a sample of body fluid to an analysing system and a kit for delivering blood serum comprising such a syringe.

Description

Method for delivering a sample of body fluid to an analysing system, a syringe designed for use therein and a kit comprising such a syringe

The invention relates to a method for delivering a sample of body fluid, and in particular blood, to an analysing system. The invention comprises also a syringe for drawing blood and delivering blood serum for biomedical tests, and a kit for delivering blood serum comprising such a syringe.

Nowadays various blood tests have become primary, commonly performed medical tests. A blood sample is to be collected from a patient, followed by subsequent separation of the blood cells (hematocytes, hematocrit) from the plasma (serum), and finally appropriate biochemical tests are carried out on the serum samples.

Blood samples from patients are obtained using standard syringes with needles or -at present mostly - using special vacuum vessels (tubes), made of glass or plastic, with a tight stopper and a fitted element with needle. The needle is inserted in a blood vessel and the tube, initially empty, is shortly filed with blood. Then, the tube is disconnected from the needle, which results in a blood containing tube tightly closed with the stopper. If necessary, another empty tube may be subsequently connected to the needle. Usually, both elements described here are disposable to guarantee the necessary sterility. The said tubes with needles are known, for instance, from publications: US 2010323437 Al , KR 20080025050 A, or JP 200018940ό A. Typically, the tubes are a few centimetres long, and their typical volumes range from a few hundred microliters to a few mililiters. It is also possible to collect a drop of capillary blood from the finger to a capillary that is wetted by blood. In such a procedure, blood is collected to the capillary and fills a tube that is appropriately prepared and connected to the capillary; the capillary is disconnected after the blood collection is completed. Blood cells are separated from plasma mostly by centrifuging blood closed in a vessel (e.g., in a tube mentioned in the paragraph above) in a centrifuge. The centrifuging results in blood cells (hematocrit) precipitated at the bottom of the tube, with the plasma (serum) above them.

The tubes so prepared are placed essentially vertically in racks and analysed in biochemical analysers.

Biochemical analysers are advanced automated devices used for testing chemical composition of the blood serum. For instance, the method is used to determine the blood content of the following substances: glucose, lipids (e.g., cholesterol, triglycerides), enzymes or ions. With a set of needles and an appropriate mechanism, the analyser draws a serum sample from the tube and mixes it in a small cuvette with appropriately selected reagents, which allows - for instance by photometric analysis of products of a chemical reaction - to determine concentrations of substances of interest in the blood serum.

The biochemical analysers based on the above method and performing the test procedure described above are commercially available devices (e.g., ELITech Flexor XL systems), and are subject matter of numerous patent applications and patents (e.g., publications: JP 821 1072 A, JP 10132735 A, JP 201033924 A, US 20040185549 Al , US20050014274 Al , US 4808380, US 0102399, or US20070065945 Al ).

A separate group of analysers are systems utilising disposable discs (e.g. commercially available models Abaxis Piccolo® Xpress and Samsung IVD- A10A) containing chemical reagents that are necessary to carry out diagnostic reactions (the existing designs use freeze-dried reagents) and enabling the use of necessary biological material. These designs require that the biological material collected earlier from the patient is transferred using an external dispensing instrument (pipette). This element of the process not only increases the number of operations that are necessary to perform an analysis, but also elongates the time needed to perform the test. The number of analyses that may be performed using disc-based analysers is limited by availability of the reagents, performing correctly after the freeze-drying process. In such systems, the reagents are dispensed with the use of the centrifugal force to assure a uniform spreading out of biological material and solvent to places where the freeze-dried reagents are stored and the chemical reactions take place. Essential limitations for the accuracy of measurements performed with the disc technology-based analysers are related to the reproducibility of producing small portions of freeze-dried reagents and the reproducibility of dispensing.

It follows from the above description that the process of acquiring the blood serum needed for medical testing and delivering the serum samples to the analyser is complex, quite invasive for the patient, and requires many operations, in particular filling the tube, centrifuging the tube, and finally multiple drawing the serum from the tube for consecutive assays. In particular, the procedures known at present require a few operations related to displacing the sample and the serum between different vessels or hydraulic tubes, often requiring manual or mechanical operations to produce hydraulic connection between these vessels and/or tubes. Reduction of the number of operations performed on the sample and the serum would be extremely preferable because of simplification of the procedure and reduction of possible errors and contaminations. Simplification of the procedure for transferring the blood plasma (serum) to the analyser allows also for preferable shortening the time from drawing blood from the patient to performing the actual analysis.

The purpose of the invention is to provide a method for acquiring the blood serum for biochemical assays, and subsequently delivering the serum to the analyser, with a minimum number of operations to be performed. According†o the invention, a method for delivering a sample of body fluid to an analysing system, comprising the steps: a) collecting the body fluid in a reservoir of a storage element, b) centrifuging the body fluid in the reservoir of the storage element, is characterised in that subsequently c) the body fluid is pushed out from the reservoir of the storage element to the analysing system.

Preferably, said body fluid is blood.

In such case, preferably, in step b) the blood is separated into plasma and blood cells by centrifuging.

Alternatively, in such case, preferably, in step b) the blood is separated into serum and hematocrit by centrifuging.

Preferably, in step c) the plasma or the serum are pushed out to the analysing system.

Preferably, a microfluidic system is used as the storage element.

In such case, preferably, in step c) the body fluid is pushed out from a chamber of the microfluidic system to the analysing system by pumping the liquid through the microfluidic system.

In such case, preferably, a liquid immiscible with the body fluid is used.

In an alternative, preferred, embodiment of the invention, a syringe is used as the storage element.

In such case, preferably, in step c) the body fluid is pushed out from the reservoir of the storage element to the analysing system by movement of the plunger, preferably moved by the operator's palm or by an appropriate mechanism. In such case, preferably, in step c) the body fluid is pushed out from the reservoir of the syringe†o the analysing system by pumping the liquid by the syringe.

The invention relates also to a syringe comprising a barrel for blood, bounded by the lateral surface, having an outlet at the first end and closed with plunger at the second end, characterised in that the said lateral surface of the barrel contains a hole, whereas the distance between the hole and the second end of the barrel is less than the length of the plunger, which allows for complete covering of the hole with the plunger by pressing the plunger into the barrel.

Preferably, the internal lateral surface of the barrel forms a capillary tube with internal diameter from 0.2 mm to 4 mm, preferably from 1 mm to 2mm.

Preferably, the internal surfaces of the barrel, the hole or the ferrule are coated with a substance accelerating blood clotting, selected from the group comprising: silica, colloidal silica, kaolin, glass particles, diatomaceous earth, thrombin based-agents, or ellagic acid.

Alternatively, preferably, the internal surfaces of the barrel, the hole or the ferrule are coated with a substance preventing blood clotting, selected from the group comprising: EDTA (salt of the ethylenediaminetetraacetic acid), trisodium citrate, heparinates (sodium, lithium, ammonium salt of heparin), hirudin, potassium oxalate, sodium fluoride, iodoacetate or thrombin inhibitors (e.g., PPACK or agratroban).

Preferably, the capillary terminal (4) is non-wettable by serum.

The invention relates also to a kit for delivering blood serum, comprising such a syringe, a microfluidic nozzle fitted to the outlet of the syringe barrel, and a centrifuge rotor, having a well used for placing the syringe therein together with installed nozzle, said well being adapted to the size and the form of the syringe with the nozzle. Preferably, af the further edge from the centrifuge's axis of rotation the centrifuge rotor has a hole, through which the syringe plunger can be pushed in while the syringe is placed in the rotor well.

Preferably, the centrifuge rotor has a hole at the place the syringe outlet is located, to allow for transferring serum from the syringe to the analyser.

Preferable embodiments of a syringe according to the invention are listed below.

According to the invention, the syringe comprising a barrel for blood, bounded by the lateral surface, having an outlet at the first end and closed with plunger at the second end, is characterised in that the said lateral surface contains a hole, whereas the distance between the hole and the second end of the barrel is less than the length of the plunger, which allows for complete covering of the hole with the plunger by pressing the plunger into the barrel.

Preferably, the length of the plunger is such that after pressing the plunger entirely into the barrel the end of the plunger faces the end of the syringe.

Preferably, the outlet is fitted with a capillary terminal.

Preferably, the internal lateral surface of the barrel forms a capillary tube with internal diameter from 0.2 mm to 4 mm, preferably from 1 mm to 2 mm.

Preferably, the length of the barrel is from 10 mm to 200 mm, more preferably from 30 mm do 70 mm.

Preferably, the hole is round, with diameter from 0.2 mm do 4 mm, preferably from 1 mm do 2 mm. Preferably, the hole has a ferrule in the form of a funnel for easy blood drawing.

Preferably, the capacity of the syringe barrel is from 20 to 1000 mm³, more preferably from 25 to 250 mm³, and most preferably from 50 to 150 mm³.

In a preferred embodiment of the invention, internal surfaces of the barrel, the hole or the ferrule are coated with a substance accelerating blood clotting, selected from the group comprising: silica, colloidal silica, kaolin, glass particles, diatomaceous earth, thrombin based-agents, or ellagic acid.

In another preferred embodiment of the invention, internal surfaces of the barrel, the hole or the ferrule are coated with a substance preventing blood clotting, selected from the group comprising : EDTA (sa lt of the ethylenediaminetetraacetic acid), trisodium citrate, heparinates (sodium, lithium, ammonium salt of heparin), hirudin, potassium oxalate, sodium fluoride, iodoacetate or thrombin inhibitors (e.g., PPACK or agratroban).

Preferably, the capillary terminal is non-wettable by serum.

Preferably, the syringe has a holder placed along the side wall of the barrel and connected therewith.

Preferably, the syringe has tabs for finger support near the second end of the barrel.

The invention comprises also a kit for delivering blood serum, comprising the above syringe, a microfluidic nozzle fitted to the outlet of the syringe barrel, and a centrifuge rotor, having a well used for placing the syringe therein together with installed nozzle, said well being adapted to the size and the form of the syringe with the nozzle.

Preferably, at the further edge from the centrifuge's axis of rotation the centrifuge rotor has a hole, through which the syringe plunger can be pushed in while the syringe is placed in the rotor well. Preferably, the centrifuge rotor has a hole at the place the syringe outlet is located, to allow for transferring serum from the syringe to the analyser.

In the meaning of the present patent application the term ,,microfluidic system " comprises any system containing a cha nnel with at least one characteristic dimension (e .g ., dia meter) not greater tha n 2 m m . The microfluidic system may be preferably fabricated from a polymer, e.g., polycarbonate, polypropylene, polyethylene, polystyrene or another polymer suitable for injection moulding. Layered systems are particularly preferable here, especially those having holes in the u pper layer, a nd microfluidic channel or channels in the lower layer.

The invention has the following advantages:

• minimisation of manual and mechanical operations consisting in setting hydraulic connections between reservoirs and tubing for collecting and transferring the body fluid to be collected, separated into components using centrifugal force and deposited/transferred (in an easy way) directly to the place where the sample (plasma, serum) will be used;

• minimisation of the physical way the body fluid has to make (by flowing) from the moment of being collected to the moment the serum (plasma) is being used - so the volume of the lost body fluid is reduced and the safety increased in the case of hazardous samples (e.g., infectious); potentially, if needed, minimisation of the surface area of vessels and tubing that are in contact with the body fluid;

• reduction of the volume of single-use materials that are subject to disposal in collection, separation and further utilisation of the body fluid; easy handling of small volume sample of the body fluid, minimisation of possible user errors and simpler design of devices required for automation of these operations; minimum time between drawing the blood necessary for analysis, and delivering the separated plasma (serum) to the analyser.

The invention is now explained more in detail in a preferred diment, with reference to the accompanying figures, wherein:

Fig. 1 shows schematically an empty syringe according to the invention in a preferred embodiment, connected to a nozzle,

Fig. 2 shows schematically a fragment of a blood-filled syringe from Fig.

1 , connected to a nozzle,

Fig. 3 shows schematically a blood-filled syringe from Fig. 1 , placed in a centrifuge rotor according to the invention,

Fig. 4 illustrates schematically delivering the serum to the analyser from the syringe according to the invention through a nozzle,

Fig. 5 presents schematically a microfluidic system (chip) according to the invention in a preferred embodiment,

Fig. 6 presents schematically the microfluidic system from Fig. 5, filled with a blood sample in a preferred embodiment,

Fig. 7 presents schematically the microfluidic system from Fig. 6, placed in a centrifuge rotor according to the invention, and

Fig. 8 illustrates schematically the microfluidic system from Fig. 6 after completed centrifugation and separation of morphotic blood elements from the serum. The following labelling is used in the drawings: 1 - barrel 2 - hole, 3 - plunger, 4 - capillary terminal, 5 - microfluidic nozzle, 6 - tube delivering the serum to the junction, 7 - sensor, 8 - outlet port, 9 - microfluidic nozzle socket, 10 - blood, 1 1 - axis of rotation, 12 - well, 13 - hole, 14 - rod, 15 - serum, 1 6 - droplet, 1 7 - hematocrit, 21 - venting hole/hole used for delivering the fluid pushing the serum (or plasma) out from the barrel, 22 - venting hole/hole used for delivering the serum (or plasma) to the analyser, 23 - hole for blood drawing, 24 - barrel, 25, 26, 27 - channels connecting respective holes with the barrel.

Preferred embodiments

Example 1 - delivering the sample using a syringe - the syringe 1

A syringe is fabricated, wherein the barrel 1 for blood is made of a polystyrene tube (external diameter 3 mm, internal diameter 2 mm, length 70 mm) . In the side wall of the tube there is a hole 2 with a diameter of 2 mm, whereas the centre of the hole 2 is located 4 mm from the end of the tube, which is used to insert the plunger 3. Preferably, the hole 2 may have a ferrule in the form of a funnel for easy blood drawing into the syringe. The syringe is fitted with a plunger 3 with the following dimensions: external diameter (at the place the connection with the tubing is sealed) - 2.05 mm, external diameter (on the remaining length) - 1 .98 mm, length - 8 mm. The plunger 3 is made of Dyneon (it is possible to fabricate the plunger 3 from other polymers, for example and non-limiting, polyvinyl chloride PVC, polypropylene PP, Teflon, Dyneon, rubbers consisting of natural, isoprene or nitrile rubbers, or possibly of a hard core-soft shell composite - sealing; besides, most typical polymers may be used. The capacity of the syringe in the embodiment presented here is 200 μΙ_. Based on the above description, persons skilled in the art will be easily able to fabricate syringes according to the invention with capacities of interest, in particular ranging from 20 L to 1 000 μΙ_, by modifying the length and/or the diameter of the syringe barrel 1 . The plunger 3 jest set in the tube at the depth of 3 mm, so as not to cover the hole 2.

An optional part of the syringe is a holder (not shown in the drawing) - the holder (e.g., in the form of a rectangle) may be located along the tube that is the body of the syringe and be connected with the body. It may also be created in the form of a flat 'fin' attached to the syringe body. Such a holder may be also used for labelling the sample to be collected (e.g., with a bar code label). The tube 1 , the hole 2 and the ferrule (not shown in the drawing) may contain on their internal surfaces substances deposited by evaporation that are desirable with regard to the final result of the blood separation. These substances may be used to prevent blood coagulation, for example and non-limiting: EDTA (salt of the ethylenediaminetetraacetic acid), trisodium citrate, heparinates (sodium, lithium, ammonium salt of heparin), hirudin, potassium oxalate, sodium fluoride, iodoacetate or thrombin inhibitors (e.g., PPACK or agratroban). These substances may also be used to activate blood coagulation, for example and non-limiting: silica, kaolin, glass particles, diatomaceous earth, thrombin based-agents, or ellagic acid.

Optionally, the syringe according to the invention may have a finger support at the plunger 3.

Optionally, the syringe according to the invention may have in the barrel 1 an additional inlet at the place the blood 10 is located, and preferably at the place the serum (plasma) 15 is located after centrifuging and separation. Such an inlet is not shown in the drawing. This inlet allows for delivering (after centrifuging and separation) a fluid immiscible with the serum (plasma) 15 (e.g., oil) and pushing out a desired serum (plasma) 15 portion from the barrel 1 using an applied flow of this immiscible fluid.

The syringe - according to the invention - is used as follows:

The patient puts pricked finger to the hole 2. The blood 10 is aspired to the syringe spontaneously, due to capillary forces. In the case of the syringe discussed here an adult fills it within about 30 seconds, whereas the amount of blood collected and sufficient for blood testing is only 0.2 ml, i.e., about ten times less than for traditional syringes or blood collection tubes mentioned in the introduction. After filling the syringe with blood, the plunger 3 is pressed in to the depth of 8 mm (so that it entirely fits in the tube) - resulting in the hole 2 in the side wall being closed by the plunger 3. The plunger 3 is designed so as to be able to be pushed to the end of the barrel 1 with no risk to be pushed in too deeply. At the end, the syringe has a capillary terminal 4, allowing to connect the syringe outlet with a microfluidic nozzle 5, fitted with a serum sensor 7 (optical or electrical) and terminated with the outlet 8. Preferably, the nozzle 5 contains a socket 9, allowing to insert the terminal 4.

The syringe is placed in the centrifuge rotor so that the outlet 8 of the microfluidic nozzle 5 points towards the axis of rotation 1 1 , and the plunger 3 points outwards from the axis of rotation 1 1 , and during centrifuging prevents the collected material 10 from flowing out.

The centrifuge rotor has a well 12 adapted to the size and the form of the syringe. The rotor is made of aluminium (or other suitable material - for instance ABS, polyacetal (POM), polystyrene or polyamide 66 with a fiber glass filler). After centrifugation, the blood 10 is separated into the serum 15 and the hematocrit 17, whereas the serum 15 is positioned closer to the axis of rotation 1 1 and the syringe outlet, and the hematocrit 17 - further from the axis of rotation 1 1 and the syringe outlet. In addition, at its edge the rotor has holes 13, allowing to insert from outside a rod 14 pressing the plunger 3, in order to initiate the flow of the separated serum 15 and deliver it for further processing, e.g., to an analysing system (not shown in the drawing). The serum 15 flows out through additional holes in the rotor (positioned closer to its centre). In particular, it is possible to connect the syringe with a nozzle used for producing droplets 16 and to place such an assembly jointly in the centrifuge rotor. That's why after blood collection and centrifuging, necessary serum portions can be dispensed through the nozzle 4 into the analysing system (not shown in the drawing) without removing the syringe from the rotor. Preferably, the rotor contains additionally a hole at the place the end of the syringe is located (closer to the axis of rotation 1 1 ).

The centrifuging must be carried out by setting appropriate time and rotational speed. The parameters of centrifugation - time and rotational speed, e.g., 15 minutes at 3000 rpm, or 2 minutes at 8000 rpm - are known to those skilled in the diagnostic testing.

After centrifuging, one obtains the serum 15 in the syringe (located closer to the syringe outlet) and the blood cells 17 (located closer to the plunger 3). Now, the plunger 3 may be pressed into the tube 1 , which results in pushing out the serum 15 from the syringe and transferring it through the microfluidic nozzle 4 to the analysing system (not shown in the drawing).

Example 2 - delivering the sample using a syringe with conventional plunger

Classical syringe with plunger, known from the state of the art, after filling with whole blood (possibly with addition of an anticoagulant or clotting substances) is placed in the centrifuge rotor so that the syringe outlet points towards the axis of rotation, and the plunger points outwards - from the axis of rotation and during centrifuging prevents the collected material from flowing out.

The centrifuging is carried out according to parameters given below.

After centrifugation, serum or plasma (located closer to the syringe outlet) and hematocrit (located closer to the plunger) are obtained in the syringe. Now, by pressing the plunger the serum or the plasma may be pushed out from the syringe and transferred - for example through a microfluidic nozzle - to an analysing system.

A series of tests with various rotational speeds and centrifugation times has been carried out for the system presented above. The tables below show the data from performed analyses: Rotational Time Serum Plasma speed [rpm] [min] volume [%] volume [%]

8000 2 32 54

8000 2 27 50

8000 2.5 46 54

8000 5 50 55

As the plasma yield was higher than the serum yield, further stages of testing have focused mainly on obtaining the plasma.

Centrifugotion tests with anticoagulant (heparin) are presented below:

Analysing the results presented here one can notice that the plasma yield (41 % - 58%) obtained in the centrifugation corresponds to the generally accepted standards for centrifugation of the whole blood (40% -60%). Example 3 - delivering the sample using a microfluidic system (chip)

A two-layered microfluidic chip has been fabricated, wherein the lower layer consists of channels and a chamber for the blood sample. The upper plate has three holes including the hole 23 allowing to apply the blood sample directly from the patient' s finger. Optionally, the hole 23 can be adapted for installation of capillaries or a funnel for easy blood collection. The hole 22 used for delivering serum (or plasma) to an analyser can be optionally adapted for installation of capillaries for easy transfer of the fluid. For those skilled in the art it is obvious that each hole (21 , 22, or 23) may be used for blood sample collection, and additionally each hole can be placed both in the upper and in the lower plate, and on the external edge resulting from joining the plates. It is essential that the hole 21 with the channel 25 are used after the centrifugation is completed, to push out the serum (or plasma) obtained, and that the hole 22 with the channel 26 are used for delivering the serum to the analyser - during this operation the hole 23 must be closed. It is noteworthy that the inlet of the channel 25 to the chamber 24 should take into account the biological variability of the material being collected so that after separation the blood cells are below that inlet. Both layers of the system have been durably joined so as to maintain the necessary tightness of the entire microfluidic system.

The capacity of the entire microfluidic system in the embodiment discussed here is about 150 μΙ_, and the width of the channels inside the chip (25, 20, and 27) is 1 mm.

The chip's internal channels may contain on their surfaces substances deposited by evaporation that are desirable with regard to the final result of the blood separation. These substa nces may be used to prevent blood coagulation, for exa m ple a nd non-limiting including: EDTA (salt of the ethylenediaminetetraacetic acid), trisodium citrate, heparinates (sodium, lithium, ammonium salt of heparin), hirudin, potassium oxalate, sodium fluoride, iodoacefafe or thrombin inhibitors (e.g., PPACK or agratroban). These substances may also be used to activate blood coagulation, for example and non-limiting including: silica, kaolin, glass particles, diatomaceous earth, thrombin based-agents, or ellagic acid.

The microfluidic system - according to the invention - is used as follows:

The patient puts pricked finger to the hole on the chip surface. The blood is aspired to the system spontaneously, due to capillary forces. In the case of the system discussed here an adult fills it within about 30 seconds, whereas the amount of blood collected with this method and sufficient for blood testing is only 0.15 cm³, i.e., about ten times less than for traditional syringes or blood collection tubes mentioned in the introduction. After filling the chip with blood, it is placed in a specially prepared rotor (Fig. 3). The centrifuge rotor has a well adapted to the size and the form of the system. The rotor is made of aluminium (or other suitable material - for example ABS, polyacetal (POM), polystyrene or polyamide 66 with a fiber glass filler) . After centrifugation, the blood is separated into the plasma (or serum) and the hematocrit, whereas the plasma is positioned closer to the axis of rotation in the microfluidic chamber, and the hematocrit - further from the axis of rotation. In addition, the rotor and the chip have holes, allowing to deliver oil through a hydraulic system, whereas said oil is used to dispense the plasma in portions to an analysing system (not shown in the drawing) . By pumping oil to the microfluidic system a portion of plasma is pushed out from the system. The plasma flows out through a hole in the rotor.

The centrifugation must be carried out by setting appropriate time and rotational speed. The parameters of centrifugation - time and rotational speed, e.g., 3 minutes at 8000 rpm - are known to those skilled in the diagnostic testing.

A series of tests with various rotational speeds and centrifugation times has been carried out for the microfluidic system presented above. The table below shows the obtained plasma yields:

For a person skilled in the art it is evident that a specific plasma yield (for an adult from 35 to 60% on average) may be assured by using rotational speeds and centrifugation times different than those mentioned above, in particular higher rotational speeds and shorter times.

Claims

1 . A method for delivering a sample of body fluid to an analysing system, comprising the steps: a) collecting the body fluid in a reservoir of a storage element, b) centrifuging the body fluid in the reservoir of the storage element, characterised in that subsequently c) the body fluid is pushed out from the reservoir (4, 24) of the storage element to the analysing system.

2. Method according to claim 1 , characterised in that the said body fluid is blood.

3. Method according to claim 2, characterised in that in step b) the blood is separated into plasma and blood cells by centrifuging.

4. Method according to claim 2, characterised in that in step b) the blood is separated into serum and hematocrit by centrifuging.

5. Method according to claim 3 or 4, characterised in that in step c) the plasma or the serum are pushed out to the analysing system. ό. Method according to any of the foregoing claims, characterised in that a microfluidic system is used as the storage element.

7. Method according to claim 6, characterised in that in step c) the body fluid is pushed out from a chamber (24) of the microfluidic system to the analysing system by pumping the liquid through the microfluidic system.

8. Method according to claim 7, characterised in that a liquid immiscible with the body fluid is used.

9. Method according to a ny of the foregoing claims from 1 do 5, characterised in that a syringe is used as the storage element.

10. Method according to claim 9, characterised in that in step c) the body fluid is pushed out from the reservoir of the storage element to the analysing system by movement of the plunger, preferably moved by the operator's palm or by an appropriate mechanism.

1 1 .Method according to claim 9 or 10 characterised in that in step c) the body fluid is pushed out from the reservoir of the syringe to the analysing system by pumping the liquid by the syringe.

12. A syringe comprising a barrel for blood ( 1 ), bounded by the lateral surface, having an outlet at the first end and closed with plunger (3) at the second end, characterised in that the said lateral surface of the barrel (1 ) contains a hole (2), whereas the distance between the hole (2) and the second end of the barrel (1 ) is less than the length of the plunger (3), which allows for complete covering of the hole (2) with the plunger (3) by pressing the plunger (3) into the barrel (1 ).

13. Syringe according to claim 12, characterised in that the internal lateral surface of the barrel ( 1 ) forms a capillary tube with internal diameter from 0.2 mm to 4 mm, preferably from 1 mm to 2 mm.

14. Syringe according to claim 12 or 13, characterised in that the internal surfaces of the barrel (1 ), the hole (2) or the ferrule are coated with a substance accelerating blood clotting, selected from the group comprising: silica, colloidal silica, kaolin, glass particles, diatomaceous earth, thrombin based-agents, or ellagic acid.

15. Syringe according to claim 12, or 13, characterised in that the internal surfaces of the barrel (1 ), the hole (2) or the ferrule are coated with a substance preventing blood clotting, selected from the group comprising: EDTA (salt of the ethylenediaminetetraacetic acid), trisodium citrate, heparinates (sodium, lithium, ammonium salt of heparin), hirudin, potassium oxalate, sodium fluoride, iodoacetate or thrombin inhibitors (e.g., PPACK or agratroban). 1 ό. Syringe according†o claim 12, 13 or 14, characterised in that the capillary terminal (4) is non-wettable by serum.

17. A kit for delivering blood serum, comprising a syringe according to any of the foregoing claims from 12 to 16, a microfluidic nozzle (5) fitted to the outlet of the syringe barrel (1 ), and a centrifuge rotor, having a well (12) used for placing the syringe therein together with installed nozzle (5), said well being adapted to the size and the form of the syringe with the nozzle.

18. Kit according to claim 17, characterised in that at the further edge from the centrifuge's axis of rotation (1 1 ) the centrifuge rotor has a hole (13), through which the syringe plunger (3) can be pushed in while the syringe is placed in the rotor well (12).

19. it according to claim 1 7 or 18, characterised in that the centrifuge rotor has a hole at the place the syringe outlet is located, to allow for transferring serum (15) from the syringe to the analyser.