EVALUATION OF PROTEIN CONTAINING QUALITY-CONTROL MATERIALS FOR BLOOD-GAS ANALYSIS

Protein containing quality control (QC) material in ampoules for blood gas, pH and electrolyte analysers has been manufactured using buffere d protein (Bovine Serum Albumine, BSA) solution with sodium bicarbonat e and chloride salts. For comparison a similar QC material but without protein was manufactured. Results obtained with ampouled QC material depend on pre-analytical effects, on matrix effects and on the stabili ty of the material. Pre-analytical variation occurs with closed and/or opened ampoules. The shaking rate of the ampoule must be high (vortex ing) and the duration of shaking long enough (15 seconds) to give good reproducibility. Temperature coefficients of protein containing contr ols are equal to those of protein free controls when incubated at diff erent temperatures. Vigorously shaking of the ampoule gives a protein foam layer resulting in stable values for pH, pCO(2) and pO(2) during maximally 6 minutes after opening of the ampoule. Concerning matrix ef fects the CO2 buffer capacity of protein containing QC material is sli ghtly higher compared to that of protein free QC materials as determin ed by tonometry with CO2/air gas mixtures and measuring pH and plottin g log pCO(2) vs. pH. The O-2 buffer capacity measured as the bias on a properly functioning blood gas analyser is smaller than the bias of p rotein free QC material. The protein containing quality control is sta ble for at least 12 months when stored refrigerated at 2-6 degrees C a nd 28 days at room temperature.