Specimen submission guidelines
The following guidelines are intended to
assist you in preparing optimal specimens for cytologic
evaluation. If you have questions about specimen submission, call the cytology laboratory
between
8 a.m. and 5 p.m., Monday-Friday.
General tips
An adequate clinical history is often vital, both for diagnostic purposes and
to assure proper laboratory
workup (special stains for organisms, flow cytometry or immunostains for lymph node
aspirates in
suspected lymphoma etc.). Since not all tests can be performed in the case of every
specimen, appropriate
history enables the cytopathologist to direct a more efficient and rapid workup.
If multiple sites are sampled, label each individually if a site-specific diagnosis is
needed for clinical
management.
Fine needle aspiration (FNA)
FNAs can be performed on a superficial (palpable) mass or on a deep-seated
lesion under radiographic
guidance. For a superficial FNA:
1) A thin (most commonly a 23 or 25 gauge) needle is attached to a 10 or 20 cc syringe.
2) The needle is inserted into the mass. Negative pressure is introduced by pulling back
on the syringe
plunger.
3) The needle is rapidly moved back and forth in small excursions within the mass while
suction is
maintained. As the needle is nearly (but not completely)
withdrawn from the mass, the angle of entry
may be slightly altered so that a different region of the mass is
sampled. Disaggregation of cells is
accomplished by the cutting action of the needle.
4) The plunger of the syringe is released, after which the needle is withdrawn.
5) The aspirated material is ejected onto a glass slide and a second slide used to spread
the material
in a thin, even film.
6) The prepared slide is immediately fixed in 95% ethanol or sprayed with a suitable
fixative. A delay in
fixation of even a few seconds may cause drying artifact which
distorts the cells sufficiently to interfere
with an accurate diagnosis. For some lesions (i.e. enlarged lymph
nodes or thyroid nodules) it is helpful
to submit both fixed smears and one or more unfixed slides for
later staining by the laboratory.
7) The needle may be rinsed in Saccomanno fixative or a cell culture medium such as RPMI,
which is sent
to the laboratory so that other preparations such as cytospins
and cell blocks can be made.
8) If liquid material is aspirated from cystic lesions, it can be submitted in a sterile
container to the cytology
laboratory. If such material contains abundant blood, it can be
heparinized by adding a small amount of
heparin mixed in normal saline.
FNAs can be performed by a clinician or a cytopathologist. The advantages of a pathologist
doing the
procedure are that a rapid evaluation can be rendered regarding adequacy of the aspirated
material and
need for repeating the procedure (usually a minimum of 2-3 passes with the needle are
necessary to assure
an adequately cellular sample). In addition, the pathologist can direct the distribution
of aspirated material
for other tests, such as microbiologic culture, flow cytometry and electron microscopy, as
indicated by
preliminary evaluation of the smears. To schedule an outpatient FNA (performed in the ENT
Clinic on the
1st floor of Hermann Hospital) call the cytology laboratory at (713) 704-6464; specify
that the pathologist
is to perform the aspiration.
Tzanck smears
Select and unroof an intact vesicle. Scrape the base of the lesion with a
scalpel blade and spread the
material in a thin film on a glass slide, immediately immersing the slide
in 95% ethanol or spraying it
with an appropriate cytologic fixative (air-drying causes cellular enlargement/distortion
which may make
it impossible to reliably diagnose viral-induced nuclear changes. Slides should be clearly
labeled with
the patient's name.
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