You hit the nail on the head regarding the US medical establishment. We
technologists only do testing per doctor's orders. There are compliance
issues i.e. we can't do anything that doesn't have a test order backing
it up. If we come up with an incidental finding (something positive
that wasn't ordered, for example) we have to get a doctor's order in
order to report it out. The insurance companies of course want to keep
unnecessary testing volume down. I must say O&P is an often requested
test that usually comes up with negative results. We have a positive
maybe once every two weeks or less, and we do from 5-10 a day on
average. Our population in the northern midwest, though, is pretty
stable. Big coastal cities obviously have more of an influx of people
with more "exotic" travel backgrounds and probably a higher likelihood
of parasite recovery.
You're right about global travel. That's why our check samples include
exotic parasites, in that we never know where our patients have been.
Unfortunately, there was nothing in your pictures that looked like a
worm or ova. Sorry. Once you've seen the parasites, they look EXACTLY
like they do on the web sites. They fall within the proper measurement
criteria, and, when you see them, you ask yourself "why did I think that
was a parasite when this obviously is one?"
Part of MT training is to teach students about all the pitfalls of
reading O&P's. There are many microscopic elements in feces that can
look "important" but are not parasites. You have to develop an eye for
seeing past all the floating garbage on the slide and look for certain
things that ring bells that say "that is a parasite or potential
parasite." One of those things is light refraction under the scope.
Parasites "catch your eye." They have definite cell walls. The ova
have internal structure. They have size reproducibility on the prep
(i.e. every one you see will be the same micrometer size), give or take
a couple of microns. We also have staining techniques that will show
trophozoite forms that are not easily recoverable on a wet prep. We mix
some of the feces with PVA (poly-vinyl alcohol) on a slide and let the
specimen dry overnight. We then stain it with trichrome stain (a fairly
long and complex staining procedure). We then coverslip the stains, let
those dry, and then look at them under an oil-immersion lens. This all
takes quite a bit of time, reagents, and expertise. Our concentration
procedure is done with formalin (definitely not something you want to
mess with at home) and ethyl acetate. This allows ova to settle out at
the bottom of a test tube after centrifugation at low speeds (not
something you have at home either) and permits sighting of more
parasites than you would just taking some feces, mixing with saline, and
looking under the scope.
We coverslip all preparations, and have good scopes to look through. We
also use Lugol's iodine on the concentrates to enhance the structures.
There are procedures in every lab for all of this. All reagents have to
be stored in special cabinets. Formalin exposure in some labs are
monitored closely (with the little we use, it's not a problem, but
formalin exposure in Histology departments is monitored, as they use a
lot more than we do).
Hope this explains why this is not a do-at-home project.
Good luck.
Judy Dilworth, M.T. (ASCP)
Microbiology
Wilf Russell wrote:
> You just hit the nail on the head there. How does one get to a tech
> when the docs "kiss it off" as you say? Most labs and medical tests
> require authorization by an MD, and as you have acknowledged,
> convincing a doctor to do what YOU want to do is near impossible.
> (not to mention that I'm guessing insurance companies encourage them
> to do as few tests as possible).......
