Evaluation of syringes for ionized calcium measurements.
Commercially available ready to use syringes (Radiometer, Sarstedt, Ciba-Corning and Portex), containing heparinate as an anticoagulant have been tested to evaluate the magnitude of induced preanalytical errors. Tonometered serum pools adjusted to four Ca2+ concentrations were sampled anaerobically.


METHODS
Ca2+ and pH (ICA2 with 3 digits, Radiometer Medical A/S, Denmark; Heparin: anti-Xa factor activity on a chromogenic substrate. Results were expressed as means of 10 measurements and as percentages of the reference values. Sarstedt syringes, (Li-heparinate), yielded a negative bias (-3%). However for 0.5 or 1 mL samples the bias reached -4% to -6%. Radiometer syringes (QS50 and QS90; calcium titrated heparinate) demonstrated biases below -2%. The bias in the Ciba-Corning (Gas-Lyte) syringe was below 2%. Portex (Pulsator) syringes showed biases above +4% even for nominal sampling volumes. All syringes (except Pulsator) released anticoagulant amounts corresponding to the expected values. Radiometer and Ciba-Corning were the only recommendable devices.
Sachs
C
C
Department of Physiology, Necker Enfants Malades Hospital, Paris, France.
Rabouine
P
P
Dautzenberg
M D
MD
D000925:Anticoagulants; D001800:Blood Specimen Collection / Q000295:instrumentation; D002118:Calcium / Q000032:analysis* / Q000097:blood*; D005069:Evaluation Studies as Topic; D006493:Heparin / Q000032:analysis; D006801:Humans; D007477:Ions; D012015:Reference Standards; D013594:Syringes / Q000592:standards*
D000925:Anticoagulants; D007477:Ions; D006493:Heparin; D002118:Calcium