I totally agree with Jonathan that a concerted effort is now needed to sort
this problem out. Everybody who measures testosterone in female samples
should at least read the article in Clinical Chemistry and ask searching
questions of their suppliers as to the validity of their assays. For whatever
reason (poor precision, cross reaction etc.) many of the female
testosterone results obtained using direct assays are wrong (usually
resulting in incorrectly high levels being reported). I think that in the first
instance laboratory staff can help by ensuring that no female testosterone
results which may indicate serious pathology (>5.0 nmol/l) are sent out
without being confirmed by an extraction technique. In the Clin Chem
article even these techniques were shown not to be ideal but in our hands
the extraction assay gives lower results (to a greater or lesser degree) than
the direct method in nearly all samples. Some samples with results >5.0
nmol/l by the direct method end up back in the reference range (<2.4) after
extraction. Of course those patients that still have a high testosterone level
after extraction are the ones that need further investigation.
John Kane
Date sent: Mon, 28 Jul 2003 14:10:17 +0100
Send reply to: JG MIDDLE <[log in to unmask]>
From: JG MIDDLE <[log in to unmask]>
Subject: Testosterone assays better than guessing?
To: [log in to unmask]
> Listmembers who have agonised over which testosterone assay to use in
> women should be aware that a random number generator may be just as
> useful!
>
> The latest edition of Clinical Chemistry includes an article
> describing a major comparison study of commercial immunoassays with
> ID-GCMS (the reference method), and an Editorial deploring the current
> state-of-the-art of testosterone assays.
>
> Go here for links
> http://www.ukneqas.org.uk/saf01.htm
>
> To those who have followed the UK NEQAS ID-GCMS exercises over the
> years (you can download a pdf of the latest one for testosterone from
> the SAF link), these findings will come as no surprise.
>
> A major collaborative effort between laboratory, clinical and industry
> personnel is needed to address this issue.
>
> Useful discussions were had at the UK NEQAS SAF meeting last December;
> more concerted action is needed now.
>
> Jonathan Middle
>
>
>
> UK NEQAS Birmingham
> tel 0121 414 7300, fax 0121 414 1179
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> The opinions expressed are mine alone and do not necessarily represent
> those of UK NEQAS Birmingham, the UK NEQAS Organisation, the
> University Hospital Birmingham NHS Trust or University of Birmingham.
>
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Mr. John Kane
Clinical Biochemistry Dept
Hope Hospital
Salford
M6 8HD
Tel. 0161 787 4374
Fax. 0161 788 7443
Email [log in to unmask]
Website :- http://www.johnsgarden.co.uk/
------ACB discussion List Information--------
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Please note, archived messages are public and can be viewed
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