Has anyone else noticed a problem with the Vitrous Cholesterol assay?
Specifically, we have observed that sera with any degree of visible lipemia will show a higher Total Cholesterol value after dilution (and multiplication) than the value on the straight serum. The (higher) diluted values are more consistent with an alternate method. While most variances are small (~ 5%), some are huge (~ 50%).
This problem was present previously but did not occur with values less than the linearity limit of the assay. Therefore, in the past, any sample requiring dilution would have been "flagged" by the instrument. That is not the current case.
Michael McNeely MD FRCPC
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