Acid Fast Bacilli (AFB) Smear
|Synonym(s):||Smear, Concentrated (AFB) smear|
|Test Description||Microscopic Examination of Clinical Specimen for Acid-Fast Bacilli (AFB)|
|Supplemental Information Required||N/A|
|Performed on Specimens from (sources)||Clinical specimen|
|Sample/Specimen Type for Testing||
|Minimum Volume/Size Required||3 mL to 15 mL|
|Storage/Preservation Prior to Shipping||Transport specimen as soon as possible. If transport is delayed over one hour, refrigerate specimen.|
Do not use transport medium.
|Shipping and Specimen Handling Requirements||
Ship on frozen cold packs if at all possible!
|Method||Truant’s Acid Fast Stain|
|Turn-around Time||24 hours|
|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||
|Additional Information||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.|