Determination of circulating hemoglobin mass and related quantities by using capillary blood

Purpose: A standardized carbon monoxide (CO) rebreathing procedure with mea surements of GO-hemoglobin, hemoglobin concentration ([Hb]), and hematocrit (Hct) enables to determine total Hb mass (Hb(tot)), blood, erythrocyte, an d plasma Volume (BV, EV, and PV). These calculations are normally based on venous blood samples. However, micromethods also allow determinations from capillary blood. Methods: The accuracy of using capillary blood for Hb(tot) , BV, EV, and PV determination was evaluated in 42 men (age: 25.1 +/- 4.0 y r, body mass: 80.3 +/- 9.6 kg) by comparison of capillary and venous data. Results: Capillary Hb(tot) (962 +/- 110 g) did not differ from venous value s (959 +/- 106 g). Hb(tot) values were highly correlated (r = 0.987, P < 0. 001, SEE 18 g). Also, capillary and venous BV, PV, and EV were highly corre lated (0.94 < r < 0.98), but slightly different (-2.7 to 0.98) because of h igher capillary than venous [Hb] and Her. Coefficients of variation of repe ated Hb(tot), EV, PV, and BV measurements (3.0-5.2%) were similar in capill ary and venous blood. Conclusion: Calculation of Hb(tot) using capillary bl ood is as accurate and reliable as using venous blood.