Analysis for carboxyhemoglobin by gas chromatography and multicomponent spectrophotometry compared.

Measurements of carboxyhemoglobin (HbCO) by gas chromatography (GC) were compared with those obtained by multicomponent spectrophotometric analysis (MCA). Correlation was good for HbCO ranges (proportion of total hemoglobin) of 1.5 to less than or equal to 5% (GC = 0.94 MCA + 0.37%, n = 25, r = 0.98); 5.0 to less than or equal to 10.0% (GC = 0.89 MCA + 0.63%, n = 19, r = 0.93); greater than 10% (GC = 1.01 MCA - 0.02%, n = 22, r = 0.99); and greater than 0% (GC = 1.01 MCA - 0.10%, n = 95, r = 1.00). The correlation is lower for the clinically normal range of 0 to less than or equal to 1.5% (GC = 0.65 MCA + 0.24%, n = 29, r = 0.87). The gas-chromatographic method is linear for HbCO proportions of 30% to as little as 0.15%. Re-analysis of blood samples after two-month storage at 4 degrees C showed that samples remained stable under these conditions.