Hyperkalemia Hyperkalemia may only become apparent when a person's platelet concentration is more than 500,000/microL in a clotted blood sample (serum blood sample). Potassium leaks out of platelets after clotting has occurred. On the other hand, processing of heparinised, unclot blood does not cause falsely elevated potassium. In addition to that, high white cell count (greater than 120,000/microL) in patient with chronic lymphocytic leukemia increases red blood cells fragility, thus causing pseudohyperkalemia during blood processing. This problem can be avoided by processing serum samples, because formation of clot protect the cells from haemolysis during processing. A familial form of pseudohyperkalemia may
Activated clotting time of comparison due to inconsistencies between the source and formulation of the activator being used. It is usually ordered in situations where the partial thromboplastin time (PTT) test may take an excessive amount of time to process or is not clinically useful. Prolongation of the ACT may indicate a deficiency in coagulation factors, thrombocytopenia or platelet dysfunction. Clotting time measurements can be affected by other drugs that such as Warfarin, aprotinin and GPIIb/IIIa inhibitors and may also be affected by physical perturbations to the body such as hypothermia, hypervolemia or hypovolemia. Activated clotting time Activated clotting time (ACT), also known