Research of the system of hemostasis

The venous blood is taken by a nurse, capillary blood is a laboratory assistant. Blood from the vein of the examinee is taken in the morning on an empty stomach by puncturing the ulnar vein with a dry sharp short needle with a wide lumen without a syringe( preferably without applying a tourniquet to the arm).In poorly visible veins, we allow short-term venostasis - only during the insertion of the needle into the vein by applying a slight constriction, not more than 30 mm Hg. Art. It is permissible to make a light massage of the forearm in the direction from the wrist to the elbow fold. The first 5-6 drops of blood are released on a cotton swab, because they can contain tissue thromboplastin.

Blood is collected into tubes by free current, mixing it with an anticoagulant by rocking or slightly shaking, preventing the formation of air bubbles. Before centrifugation, the tubes are placed in an ice bath( a mug with ice and water).

The interval between blood sampling and the beginning of the test affects many parameters of the coagulogram, therefore, in the results of the analysis, it is necessary to note the time of taking the blood and conducting the study so that when observing the dynamics the time interval is the same and the results are comparable.

Tubes should be glass silicone or plastic, dimensional or have a mark to which blood should be drawn, so that the correct ratio of blood and anticoagulant is equal to 9: 1 if the hematocrit is close to normal. As an anticoagulant, it is recommended to use 3.8% sodium citrate solution, since labile coagulation factors and platelets are better preserved in citrated blood( plasma).A solution of sodium oxalate( 1.34%) is used in a limited way, since oxalates form a soluble compound with calcium( a fine granularity appears in the plasma), platelet aggregation is accelerating the inactivation of V and VIII factors. Plasma is prepared by centrifugation for 15-20 minutes at 3000 rpm.

In the direction of the analysis when taking bio-liquids, it is necessary to indicate:

• compartment;

• the name of the doctor who requested the analysis;

• patient data( full name, age, gender, inpatient or outpatient, number of medical history, presumed diagnosis);

• date and time of taking blood or urine;

• The purpose of the study.

Some tests may be performed from plasma derived from capillary blood( PTV).The puncture of the skin on the finger is carried out with a depth of about 4 mm. The first two drops of blood are removed, the subsequent ones are used for research. Extrude the blood from the wound is not recommended, as this increases the admixture of tissue thromboplastin. The ratio of blood and citrate is 9: 1.Blood at free drainage is collected in a collector microtube for subsequent production of serum.

The direction for analysis is signed by the doctor.

The resulting bio-liquid must be delivered to the laboratory as soon as possible. Tubes should not be filled to the brim, they must be covered with lids. Whole blood obtained without anticoagulants should not be placed in the refrigerator before delivery to the laboratory to avoid hemolysis. Centrifugation is carried out not later than 1 hour after bioavailability.