Date sent: Tue, 14 Dec 1999 14:12:27 +1100
Subject: hemolysis interference on conjugated bilirubin assay
From: Frank Alvaro <[log in to unmask]>
To: [log in to unmask]
Send reply to: Frank Alvaro <[log in to unmask]>
We have recently evaluated the Roche conjugated bilirubin assay
on the Hitachi 917 and found the method to be totally unsuitable for
use with neonatal samples for the reason you give. We intend to
revert to an in-house method with blank correction which we have
used successfully for many years on other analysers.
Best wishes
Douglas Thompson
>
> We have an Hitachi 917 analyser which performs our conjugated
> bilirubin assays (Roche H917 reagents), mostly on neonates. Most of
> the samples have some degree of hemolysis (as measured by the
> analyser, not always visible), and interference studies we have done
> show that the assay is quite sensitive to hemolysis, with results
> often coming out as negative numbers. Our interference studies have
> also shown that the degree of interference is related to both the
> degree of hemolysis and the true conjugated bilirubin concentration,
> and thus far we have not been able to construct any mathematical way
> to apply a correction.
>
> I would like to know how other labs get around this problem. I have
> tried an acidification of the R1 reagent (as suggested by another lab)
> but preliminary results show a lessening of the effect, but not
> totally removing it.
>
> ______________________________________
> Frank Alvaro
> Dept of Clinical Chemistry
> South Western Area Pathology Service
> Liverpool Hospital
> Sydney
> _______________________________________
>
Dr Douglas Thompson
Department of Clinical Biochemistry and Immunology
The General Infirmary
Leeds, LS1 3EX
Tel: 0113 3926503
Fax: 0113 2335672
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