Evaluation of the blood analyzer ABL 735 radiometer for determination of the percentage of fetal hemoglobin in fetal and neonatal blood.
OBJECTIVE
To evaluate the quality of measurements of percentage fetal hemoglobin (HbF) using the blood analyzer ABL 735 and to compare the results with the HbF measurements using the Biorad-Variant (the gold standard).


METHODS
The percentage of HbF in fetal blood, obtained during intrauterine transfusions or from the umbilical cord blood of preterm and term babies, and from the red blood cells of adults who had given blood for transfusion, was determined spectrophotometrically (ABL-735) and by high pressure liquid chromatography (Biorad-Variant). Blood pH values were also measured with the ABL 735. Reproducibility (mean difference between duplo measurements) and the relationships between the HbF percentages measured by both methods were calculated.


RESULTS
Reproducibility was independent of the HbF percentage and was more reliable with the Biorad-Variant method (0.3%) than with the ABL-735 method (2.1%). Regression analysis showed that the ABL-HbF percentages were often underestimated. Serious aberrations were observed at low pH values (<7.00) on the recalculated ABL-HbF percentages. For samples with pHs >7.00 a relatively good relationship was found between the pH-corrected ABL-HbF percentages and those of the Biorad-Variant values.


CONCLUSIONS
The HbF percentage measured with the ABL blood analyzer is only moderately accurate if the HbF percentage is corrected for the pH.
Egberts
J
J
Laboratory of Obstetrics, Leiden University Medical Center, The Netherlands. j.egberts@hccnet.nl
Van Pelt
J
J
D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D005312:Fetal Blood / Q000737:chemistry*; D005319:Fetal Hemoglobin / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn / Q000097:blood*; D011874:Radiometry / Q000295:instrumentation*; D015203:Reproducibility of Results
D005319:Fetal Hemoglobin