Specific features

Blood counts

·         EDTA- or lithium heparin blood

·         When collecting the sample, discard the first 0.5 ml of blood, if possible, as they contain an increased amount of coagulation factors, or first obtain a serum sample.

·         Let the blood slowly run down on the side of the sample tube.

·         Pay attention to the fill volume! Preferably fill up to the mark, since an insufficient volume can result in changes in cell morphology. Do not overfill the tube in any case, as the sample might clot.

·         After drawing the sample, tilt the test tube carefully several times.

  • ·         Do not store blood smears in the refrigerator and not close to formalin.
  • ·         Pack the samples frost-proof in winter; possibly cool them in summer.
  • ·         Reliable results can only be obtained from samples not older than 48 hours.

Clinical chemistry of serum or heparin plasma

Prompt centrifugation of the samples lead to better test results, as it reduces the risk of haemolysis caused by transportation. However, serum should be allowed to stand for a minimum of 30 min to ensure a complete clotting of the sample.

Serum samples can also be shipped frozen; they will then reach the laboratory cooled.

Repeated freezing/thawing, though, should absolutely be avoided.

Determination of glucose and lactate

·         Requires sodium fluoride blood or sodium oxalate blood

·         Fill the test tube up to the mark at the maximum

Coagulation parameters

  • ·         Determination is carried out using sodium citrate plasma which is obtained from citrate blood with the mix ratio being 1:10 (1 part sodium citrate + 9 parts blood). Centrifugation should take place at the practice.
  • ·         If commercial citrate-treated tubes are used, the expiry date needs to be checked before collecting the sample. Expired tubes may no longer be used, as skewed results are to be expected. When drawing the sample, special attention must be paid to the exact fill level (marking on the tube).
  • ·         If no commercial tubes are available, sodium citrate 3.13% can be drawn into a syringe.
  • ·         No heparinized needles or catheters may be used.