• We quantified coagulation parameters in vitro using standard automated methods In 12 adult patients with acute leukemia who also had Hickman catheters (HC). Test results from simultaneously obtained HC blood and control peripheral venous blood (PB) samples were compared In the respective patients. Heparin solutions (100 U/mL, US Pharmacopoeia) used to prevent the formation of clots within the HC appeared to cause, to a significant degree, spuriously elevated levels of fibrin degradation products (FDP), decreased levels of fibrinogen (FBG), and prolongations of the prothrombin time (PT) and activated partial thromboplastin time (PTT) In the first 10 mL of HC blood. The second 10 mL sample from the HC showed that FBG levels were comparable with those demonstrable in PB samples, as were levels of FDP in eight of 12 cases. Both PT and PTT times, however, remained significantly prolonged. An alternative maneuver for obtaining HC blood studied In four patients showed significant prolongation of PTT values in the second 10-mL sample despite levels of FDP, FBG, and PT similar to those in the PB. Because heparin contamination of HC blood can mimic the laboratory findings of disseminated intravascular coagulation or other coagulopathies in patients with acute leukemia, we suggest that only values obtained from PB be used for interpretation of coagulopathy in these patients.
(Arch Intern Med 1986;146:2165-2169)