To back up Mikes point about the effects of SHBG we have performed
further analysis on a number of samples which gave very discrepant
(lower) results on extraction compared to our direct automated assay
for female testosterone. We could find no apparent relationship with
SHBG levels in these samples or with other commonly measured
androgens (DHEA sulphate or androstenedione). We also analysed the
type and source of these samples and the clinical details given again
with no success. The only point we have noted is that samples from
women treated with testosterone implants usually give similar results
by both methods. This implies that natural testosterone can be
measured accurately in the female matrix by the direct method and
that the interferences seen are probably due to high levels
of steroid conjugates in certain samples.
Mr. John Kane
Clinical Biochemistry Dept
Hope Hospital
Salford
M6 8HD
Tel. 0161 787 4374
Fax. 0161 788 7443
Email [log in to unmask]
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