Bilirubin Measured on a Blood Gas Analyser: A Suitable Alternative for Near-Patient Assessment of Neonatal Jaundice?

Abstract

The reliability of a recently released total bilirubin assay for a blood gas analyser was assessed in two Australian hospital laboratories. The instrument computes total bilirubin concentration from multi-wavelength absorbance measurements of undiluted whole blood or plasma. Performance of the Radiometer ABL 735 blood gas analyser bilirubin method (software version 3.6) was compared with a proven Roche diazo method for Hitachi analysers, calibrated using primary standards prepared from NIST SRM 916a bilirubin. Acceptable bilirubin results were found over a wide concentration range for most neonatal samples of whole blood or plasma. For adult specimens, bilirubin results were approximately 10% lower on the blood gas analyser. Within-run imprecision (whole blood) was < 2.5%, between-day imprecision (synthetic controls) < 1.0%, and the bilirubin assay for both whole blood and plasma was linear to 1,000 micromol/L. Using sampling options from 35 microL to 195 microL, bilirubin results differed by less than 3%, with a 95 microL syringe option producing the highest results. We conclude that the Radiometer ABL 735 bilirubin assay is suitable for near-patient assessment of neonatal jaundice using whole blood, thus eliminating the need for sample centrifugation. Verification using laboratory methods can be used when required. A positive correction of approximately 10% is required for adult specimens to conform with Hitachi results (SRM 916a calibration), possibly due to the optical characteristics of the higher proportion of conjugated bilirubin and other substances present in most adult samples.

Comparison of Total Bilirubin Values Measured with ABL 735 Blood Gas Analyzer and Roche Cobas C8000 Chemistry Analyzer in Age-Segregated Pediatric Patients

“…Therefore, the requirement for sample preparation makes blood gas analyzers a more convenient choice. In this study, a statistically significant relationship was showed in ABL 735 blood gas analyzer and the Roche Cobas C8000 chemical analyzer as in the study by Peake et al (27). In the literature, many researchers have suggested that there is not a difference between the blood gas analyzer and the routine biochemistry analyzer.…”

“…For example, Rolinski et al concluded that the measurement of TB with the ABL 735 blood gas analyzer from whole blood samples was a promising method (28). Peake et al com-pared bilirubin results obtained on the Radiometer ABL 735 blood gas analyzer with Roche diazo method for Hitachi analyzers concluded that the Radiometer ABL 735 bilirubin assay was suitable for assessment of neonatal jaundice using whole blood, thus eliminating the need for sample centrifugation (27). There are many national and international studies comparing blood gas analyzer and biochemical autoanalyzer results, in a different source of fluid and electrolyte balance are searched (29,30).…”

Neonatal hemoglobin affects the accuracy of whole blood bilirubin measurement on GEM Premier 4000 blood gas analyzers

“…Rolinski’s study (2001) showed bilirubin on ABL 735 ​= ​1.002 x (Hitachi 917) - 4.0 ​μmol/L, with 95% CI of slope 0.914–1.090, 95%CI of intercept −22–14 ​μmol/L [ 6 ]. Another study (Peake et al., 2001) showed bilirubin on ABL735 ​= ​0.986 x (Hitachi 917) - 0.4 ​μmol/L [ 5 ]. While conjugated and delta bilirubin were excluded, bilirubin on ABL735 ​= ​0.99 (Vitros 250) ​+ ​3.4 ​μmol/L [ 7 ].…”

“…Some validation studies using neonatal whole blood samples provided conflicting correlations between blood gas analyzers and chemistry analyzers [ [5] , [6] , [7] , [8] , [9] ], which confused physicians in interpreting whole blood bilirubin results for patient management. The common causes of bias are a lack of standardized plasma bilirubin reference methods [ 10 , 11 ] and the difference in methodologies between blood gas analyzers using multiple-wavelength photometry and chemistry analyzers using diazo based assay [ [5] , [6] , [7] , [8] , [9] ].…”

“…Some validation studies using neonatal whole blood samples provided conflicting correlations between blood gas analyzers and chemistry analyzers [ [5] , [6] , [7] , [8] , [9] ], which confused physicians in interpreting whole blood bilirubin results for patient management. The common causes of bias are a lack of standardized plasma bilirubin reference methods [ 10 , 11 ] and the difference in methodologies between blood gas analyzers using multiple-wavelength photometry and chemistry analyzers using diazo based assay [ [5] , [6] , [7] , [8] , [9] ]. Other factors contributing to the bias include neonatal hemoglobin interference [ 5 , 8 ], calculation of plasma equivalency on blood gas analyzers [ 8 , 9 ], increased conjugated bilirubin or delta bilirubin in samples [ 7 ], and variable blood albumin levels [ 12 ].…”