Frank Alvaro wrote concerning correction for effects of haemolysis on
conjugated bilirubin when the effect is dependent on the concentration of
both the haemoglobin and the bilirubin.
Frank (hows things?),
A useful article may be Jay and Provasek, Clin Chem 1993;39:1804-1810. This
is (IMHO) the grandfather of all haemolysis correction papers. Included is
the treatment of 2 analytes, total bilirubin and theophylline, where the
effect you describe has occurred. They outline the use of multiple
regression analysis to cope with this situation. The maths may be a bit
tricky and I would suggest keeping a clear eye out on accumulating errors.
In the end it may be best to result as a footnote with a comment such as:
Unable to quantify bilirubin precisely due to sample haemolysis. Result
lies between X and Y umol/L. (where X and Y are the limits from the effects
of the error in the analyses and the correction).
Good luck,
Graham Jones
Staff Specialist in Chemical Pathology
St Vincent's Hospital, Sydney, Australia
Ph: (02) 9361-2170 Fax (02) 9361-2489
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