1] Nonstandard abbreviations: CAP, College of American Pathologists; UBIL, unconjugated bilirubin; CAP All Data, all results submitted to CAP; DTB, ditaurobilirubin.
Values for total bilirubin in human and bovine sera enriched with UBIL and DTB, as measured with the reference method and 7 chemistry analyzers.
Knowing that the CAP Survey specimens consist of bovine serum, rather than human serum, enriched with UBIL and DTB, we measured total bilirubin in solutions of UBIL and DTB in fresh human serum by the reference method and by the two Vitros methods.
Analysis of a specimen consisting of 102 mg/L UBIL in BSA (used because bovine serum was not available to us) with the Vitros 700 XR gave TBIL and NBIL values of 105 and 141 mg/L, respectively.
With the reference method, DTB and UBIL have similar reactivities in human serum, human serum albumin, bovine serum, and BSA.
Furthermore, the molar absorptivities of UBIL are different in human serum and BSA (7,8).