Standardization in bilirubin assays: evaluation of selected methods and stability of bilirubin solutions.

(BSA), or pooled human serum were analyzed by 1968 3 13.5 13.8 10.7-16.3 9.8-17.4 these methods. Molar absorptivities (t) of azobilirub4 4.2 14.3 3.3-5.1 3.0-5.4 in by the Jendrassik-Gr#{244}f procedure were practically 1969 C-i 15.2 10.1 12.9-17.5 12.1-18.3 identical in all three protein bases. The Meites-Hogg C-2 11.9 10.4 10.0-13.7 9.4-14.3 and Malloy-Evelyn methods gave substantially higher C-3 19.6 10.5 16.5-22.7 15.5-23.7 e values with BIL in serum than with BIL in either C-4 13.3 10.3 10.8-15.9 9.9-16.7 HSA or BSA. The precision of all methods was good, 1970 C-A 2.6 15.3 2.2-3.0 1.8-3.4 but best with the Jendrassik-Gr#{244}fprocedure. BIL C-B 14.5 13.8 12.5-16.5 10.5-18.5 standards can be prepared with good reproducibility C-C 15.8 14.6 13.5-18.1 11.2-20.4 (CV <0.5%). Standards deteriorate appreciably at 1971 C-A 3.2 12.5 2.7-3.5 2.3-3.9 -23 #{176}C but are stable at -70 #{176}C. Our data indicate C-C 3.9 10.3 3.5-4.3 3.1-4.7 a need for improved commercial BI L controls. C-D 3.8 10.5 3.4-4.2 3.0-4.6 CLIN. CHEM. 19/9, 984-993 (1973)