Synonym(s):
|
Smear,
Concentrated (AFB) smear
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Requisition Form
|
G-MYCO
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Test Description
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Microscopic Examination of Clinical
Specimen for Acid-Fast Bacilli (AFB)
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Pre-Approval
Needed
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N/A
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Supplemental
Information Required
|
N/A
|
Supplemental
Form(s)
|
N/A
|
Performed on
Specimens from (sources)
|
Clinical specimen
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Sample/Specimen
Type for Testing
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-
Sputum
- Tissue
- Exudate
- Stool
- Body
Fluids
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Minimum
Volume/Size Required
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3 mL to 15 mL
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Storage/Preservation
Prior to Shipping
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Transport specimen as soon as
possible. If transport is delayed over one hour, refrigerate specimen.
|
Transport Medium
|
Do
not use transport medium.
- A sterile, leak-proof, 50 mL conical tube preferred for primary container.
- Add up to 10 mL sterile saline to tissue, if needed to maintain moisture during transport.
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Specimen Labeling
|
- Two patient-specific identifiers required (e.g., patient full name, date of birth, Medical record number)
- Identifiers on specimen must exactly match submission form.
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Shipping and
Specimen Handling Requirements
|
- Ship according to Dangerous Goods Regulations, IATA, and/or CFR 49
- Category B shipping applies
Ship on frozen cold packs if at all possible! |
Method
|
Truant’s Acid Fast Stain
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Turn-around Time
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24 hours
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Interferences/Limitations
|
A negative microscopic
examination does not mean that the patient’s specimen cannot be culture
positive for AFB. This test is less sensitive than culture. The
stain utilizes a fluorescent dye that can be taken up by the mycobacterium to
different degrees depending on the species or if the patient is on antibiotic
treatment. The quality of the specimen has major impact on the results
of the microscopic examination.
|
Common Causes for
Rejection
|
-
Specimen leaked in transit.
- Missing identifier(s) on specimen container.
- No test requested on G-MYCO requisition form.
- Specimens received frozen, in formalin, or in culture medium will be rejected.
- Swabs are discouraged unless the only specimen available; submit swabs in 5 to 10 mL sterile saline.
- Gastric specimens must be neutralized prior to transport.
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Additional
Information
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Report
Interpretation: The report states whether the test is negative if no AFB are seen or positive if AFB are seen on microscopic examination. If positive, the report provides a quantitation to indicate how many AFB were seen in a high power field under the microscope.
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