RSV testing

Kenneth Bromberg, MD Ken_bromberg at interramp.com
Fri Jan 19 01:18:08 EST 1996


Richard Drummond wrote:
> 
>         Since there seems to be so little traffic on this news group right now
> I was wondering if everyone doing testing for RSV by a elisa is satisfied
> with their results? Has anyone looked at their culture results and compared
> them to their elisa results?
> 
>         Richard
> 
>         gip204 at freenet.mb.caAn informal discussion with my local virology laboratory suggests 
sensitivities below 90% this year.  I was involved with most of the 
original RSV kits and their field trials.  The sensitivity since thse 
trials (90-95%) seems to have decreased but this is really difficult to 
quantify.  There is so much variability with culture (look in the 
literature and you will see differing sensitivity each year for RHMK vs. 
HEp-2).  A panel of specimens, cultured at one time and then frozen in 
alequots might answer these questions as could a mixture of recombinant 
antigens.  I think the Testpack is the best test.  I've seen problems  
the Directogen (did I spell that wrong) in the low range.
	 Remember..Most DFA and EIA results during RSV season are true 
positives and that cell culture is not the gold standard.  I would 
suggest a combination of culture, antigen detection with a blocking test 
(or multiple antigen detection test during the evaluation of several 
kits) or DFA  seen by two independent observers as true positives.  We 
published some data in AM J Clin Path about using blind DFA of cells to 
find RSV that did not produce CPE because of overgrowth (? adeno) or 
other factors.
	For small numbers of samples I still like DFA. 

	The Journal of Clinical Micro is full of comparisons about these 
tests.  PCR is OK for it as well but I would consider it overkill.
	Happy wheezing.
Ken Bromberg, MD
Pediatric ID and microbiology for the fun of it.



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