[An electrolyte-adapted heparin solution for the determination of blood gases and electrolytes in whole blood].

Blood gases, pH, sodium, potassium, chloride, and ionised calcium in whole blood samples can be determined simultaneously in modern instruments. Preparing syringes with conventional heparin solutions causes a relevant bias of the electrolyte concentrations (especially K+ and Ca2+) by dilution of the sample. Additionally, ionised calcium is decreased by binding to heparin. The solution described in the present paper yields a final heparin concentration of 4-6 mU/l, thus eliminating the calcium binding effect. The dilution effects are antagonised by an electrolyte composition that is similar to normal plasma. The heparin solution is commercially available.