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ID
- AFB Slides
INTENDED
USE
ID-AFB
slide is a multi-purpose microscope slide recommended to
be part of a quality control program to monitor stains and
techniques.
PRINCIPLES
The
slide contains one oval (+) with an acid fast positive control
(Mycobacterium gordonae). The slide also contains
one oval (-) with an acid fast negative control (Eschenchia
coli). The slide contains a blank oval for the
convenience of the technologist to be utilized in performing
clinical AFB stains.
MATERIALS
PRECAUTIONS:
This product is for IN VITRO DIAGNOSTIC USE only. This product
may contain potentially viable organisms. Handle it as you
would a known pathogen.
STORAGE:
Do not freeze or expose to excessive heat. Store at room
temperature and do not use beyond expiration date.
PROCEDURE:
MATERIALS
REQUIRED BUT NOT PROVIDED: The standard clinical microbiological
equipment such as loop, burner, stains are needed for procedures
involving the use of this product.
1.
Place the specimen to be examined within confines of the
blank oval.
2.
Air dry and heat fix by gentle heating over a bunsen bumer
flame.
3.
Perform AFB stain:
a.
Flood entire stain with Kinyoun Carbol Fuchsin for
3 minutes.
b.
Wash gently in running water, rinsing both sides.
c.
Decolorize with acid alcohol until all of the color
is washed out (about 1-2 minutes depending on the
thickness of the smear).
d.
Wash gentiy in running water rinsing both sides.
e.
Counterstain with methylene blue or malachite green
for 30 seconds.
f.
Wash gently in running water rinsing both sides.
g.
Allow slide to air dry. Do not blot.
h.
Examine under microscope using oil immersion lens.
EXPECTED
RESULTS
Positive
control: red stained rod-shaped or coccobacillary bactena
(from 0.5 to 5.0 x 0.2 to 0.6 microns).
Negative
control: No red-stained bacteria. Acid fast positive organisms
stain red.
Acid
fast negative organisms stain blue or green (depending on
counterstain)
Note:
It is possible that positive control organisms can carry
over to the patient testing area. As a precaution, if a
positive patient result is recorded, repeat the testing
process on a clean slide that does not contain a positive
control organism.
LIMITATIONS
OF PROCEDURE
Acid-fast
bacteria may become nonacid-fast if they are exposed to
ultraviolet light, direct sunlight, or overheating. Saprophytic
acid-fast bacteria are found in soil and water and may contaminate
specimens during processing, resulting in a false-positive
test. (3) Heat-fixing does not always kill mycobacteria
and the specimen smear may be a potential source of infection.
REFERENCES
1.
Smithwick, R.W. 1976. Laboratory manual for acid-fast microscopy,
2nd ed. Centers for Disease Control, Atlanta.
2.
Vestal, A.L. 1978. Procedures for the isolation and identification
of mycobacteria. HEW Publication No. (CDC) 79-8230. Centers
for Disease Control, Atlanta.
3.
Dizon, D., C. Mihailescu, and H.C. Cuthbert. 1976. Simple
procedure for detection of Mycobacterium gordonae in water
causing false-positive add4ast smears. J. Clin. Microbiol.
3:211.
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