From owner-diagnostics@net.bio.net Sun May 28 23:00:00 1995
Path: biosci!ZEUS.DATASRV.CO.IL!ila2027
From: ila2027@ZEUS.DATASRV.CO.IL (Falk Fish)
Newsgroups: bionet.diagnostics
Subject: Re: HIV screening "window" & PCR
Date: 29 May 1995 14:20:01 -0700
Organization: BIOSCI International Newsgroups for Molecular Biology
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Message-ID: <Pine.3.89.1.2.9505300011.B18463-0100000@zeus.datasrv.co.il>
References: <pkramer-2805950811160001@pkramer.connix.com>
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The current window's median is about 6 months.

Theoretically, PCR should reduce the window, however, the actual 
performance does not always live to its expectations.  The problem may 
emanate from:

1. Specimen preparation problems;

2. The virus is not located in circulating periferal lymphocytes at the 
early stages of the infection.  Therefore, even very efficient 
amplification methods are unable to detect.

The are some groups working on other methods for window shrinking with 
some impressive results.

You should realize also that the window is an estimate: it is difficult, 
if not impossible, to know when the active infection started.

Falk Fish



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