Two Parasitology questionYou can very carefully add a small drop of oil and
go to oil immersion to check out details of any possible parasite. However,
this will oil up your coverslip and you won't be able to go back to high dry
on that section of your slide again. You have to move gently or the
questionable parasite under your lens will move :-(. So....you've got to be
pretty sure you've got something before you do this. I've always scanned
iodine preps under 20X and go down to 40X to check suspicious items. You can
pretty much tell on most parasites at that power. Very small parasites
require going down to oil.
I have worked as a med tech for 35 years and we've never had two readers.
However, if someone finds a positive that they're unsure of, everyone looks
at it to give their opinion. There is no advantage of making unilateral
decisions if the reader is inexperienced. This is how the reader GETS
experience. Obviously if a student is reading a slide it is rescanned by
another trained technologist.
Our laboratory has gone to Giardia/Cryptosporidium Antigen testing only
unless the patient has chronic diarrhea or a travel history, which must be
supplied by the physician. We have one client who insists on full O&P's but
for the most part we do very few of these any more. We order and cancel the
O&P test with a canned comment - that we have ordered Giardia/Crypto Ag -
and that we will save preserved specimens for three days if they want us to
perform a full O&P exam. Very few physicians have followed up with that
request. We are in Ohio so the most likely parasite in our area is Giardia.
As far as stool cultures, we are now performing Campylobacter detection via
EIA, EC O157:H7 via shigatoxin testing, and C. difficile by PCR. We culture
for Shigella, Salmonella, and Yersinia, and no longer plate for Campy or EC
Judy Dilworth, M.T. (ASCP)
"Nasir, Mohammad S." <Mohammad.Nasir from illinois.gov> wrote in message
news:mailman.369.1244581258.21502.parasite from net.bio.net...
Hello every one
I have two basic questions.
1. One technologist was telling that a concentration slide reading can
sometimes be enhanced if on top of coverslip you add an oil drop and then
look under 100X lens. I do not see it in any SOP. Any one has any experience
on that? Any pitfalls, advantages?
2. How many of you have a second reader on each slide in your SOP? Do you
rely on one reader only?
Mohammad Sarwar Nasir, Ph.D. PSA
Supervisor, Enteric and Parasitology
Illinois Department of Public Health
2121 W. Taylor Street
Chicago, IL 60612