Microscopic Examination for Sperm
There are numerous extraneous objects which are so
like the detached heads and tails of spermatozoa as to mislead
even those who are thoroughly experienced in the work. The
generally accepted rule is that no body which simply resembles the
head or tail should be considered as serious proof and the search
must continue until perfectly formed and entire spermatozoa are
recognized.
- Microscopic Examination Of Stained Slides For Spermatozoa (Reference
11)
- Equipment
- Microscope
(with approximately 200X – 400X total magnification,
with or without phase capability)
- Materials
- Distilled
water, xylene substitute, or other appropriate
mounting medium
- Coverslips
- Procedure
- Quickly
scan at approximately 200X total magnification.
Confirm at approximately 400X total magnification.
- With
phase microscopy: Spermatozoa heads are neon-like
pink/red with darker pink/purple acrosomal caps
and green tails. Epithelial cells and most
bacteria stain green with some of the nuclei
pink/red; however, these are shaped differently
than spermatozoa. Yeast cells take on the same
color as spermatozoa, but are shaped differently.
- Without
phase microscopy: Spermatozoa heads are neon-like
pink/red with pale pink (almost colorless)
acrosomal caps, blue-green necks/midpieces, and
green tails. Epithelial cells appear bright blue
with red to purple nuclei.
- Document
the approximate number of spermatozoa and spermatozoa
heads on the smear per hpf (approximately 400X total
magnification), per lpf (approximately 200X total
magnification), per length of slide, or per slide, as
appropriate.
- Place
all smears submitted in the PERK back into the PERK.
Properly label and return all other spermatozoa
positive smears with the evidence.
- Microscopic Examination Of Unstained Slides For Spermatozoa (Reference
11)
- Unstained
smears may be examined using phase contrast microscopy.
- Equipment
-
Microscope
(approximately 200X – 400X total magnification) with
phase capability
- Materials
- Microscope
slides
- Coverslips
- Applicator
sticks
- Reagents
- Procedure
-
Place a
small amount of an extract of a suspected semen stain on
a microscope slide and cover with a coverslip, or add a
drop of distilled water to a smear from the PERK, use an
applicator stick to mix the water and the material on
the smear, and cover with a coverslip.
- Scan
quickly with phase at approximately 200X total
magnification. Confirm with phase at approximately
400X total magnification.
- When
the coverslip is touched gently, the spermatozoa
and/or spermatozoa heads will roll, exhibiting their
characteristic 3-dimensional shape. Use the
distinctive size and morphology to identify the
spermatozoa/spermatozoa heads.
- Document
the approximate number of spermatozoa and spermatozoa
heads on the smear per hpf (approximately 400X total
magnification), per lpf (approximately 200X total
magnification), per length of slide, or per slide, as
appropriate.
- Place
all smears submitted in the PERK back into the PERK.
Properly label and return all other spermatozoa
positive smears.
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