The quote was not verified.
In volume 339 there are 51 issues of the 1992 Lancet.
A proper citation is needed to refer to the report.
Here are 4 hits from a 1992 Lancet search for "false positives"

55.        
False-positive immunoassay for chlamydia in urine  * CORRESPONDENCE
The Lancet, Volume 339, Issue 8806, 6 June 1992, Page 1426
E. O. Caul and I. D. Paul
Abstract | Abstract + References | PDF
http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T1B-49K5C94-3Y1-1&_cdi
=4886&_user=1083642&_orig=search&_coverDate=06%2F06%2F1992&_sk=996601193&view=c&
wchp=dGLbVtz-zSkWW&md5=cd69de7d8a1903b9c482ef11f9298a1e&ie=/sdarticle.pdf

159 K

56.        
Staphylococcus aureus in urine and
false-positive immunoassay for chlamydia
* CORRESPONDENCE
The Lancet, Volume 339, Issue 8801, 2 May 1992, Page 1110
J. Wollenhaupt, F. Hartmann, H. Zeidler and M. Frosch
Abstract | Abstract + References | PDF
http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T1B-49K58F1-1YG-1&_cdi
=4886&_user=1083642&_orig=search&_coverDate=05%2F02%2F1992&_sk=996601198&view=c&
wchp=dGLbVtz-zSkWW&md5=545c6555918a573e78c61b06a6bf698a&ie=/sdarticle.pdf

164 K
   

57.        
Detection of mycobacterial DNA in sarcoidosis and tuberculosis with
polymerase chain reaction  * ARTICLE
The Lancet, Volume 339, Issue 8800, 25 April 1992, Pages 1012-1015
S. A. Saboor, S. A. Saboor, J. McFadden and N. Mcl Johnson
Abstract | Abstract + References | PDF
http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T1B-49K57SB-1DW-1&_cdi
=4886&_user=1083642&_orig=search&_coverDate=04%2F25%2F1992&_sk=996601199&view=c&
wchp=dGLbVtz-zSkWW&md5=7462990ad3ea5ff61cfb72090ea17fc7&ie=/sdarticle.pdf

671 K
   

58.        
False-positive legionella serology in campylobacter infection  *
CORRESPONDENCE
The Lancet, Volume 339, Issue 8790, 15 February 1992, Page 429
J. S. Cheesbrough, T. Makin, B. C. Taxman, N. J. Beeching and K. J. Mutton