Test Code LAB266 ACID FAST SMEAR
Methodology
Specimens that are direct smear positive for AFB will be forward to the Maryland State Health Department for direct probe testing.
Performing Laboratory
Peninsula Regional Medical Center - Microbiology
Specimen Requirements
Submit only 1 of the following specimens:
Gastric Content
1. Collect a minimum of 3 early-morning specimens following an overnight (8 hour) fast. No preservative. (Improperly labeled specimen, specimen in leaky container, or specimen in preservative is not acceptable.)
2. Submit gastric content in a screw-capped, sterile container.
3. Label container with patient’s name (first and last), date and time of collection, type of specimen, and collector’s initials.
4. Maintain sterility and forward promptly so that specimen can be processed to neutralize adverse effects of gastric acid on Tubercle bacillus.
Note: Specimen source is required.
Sputum
Collect 3 consecutive sputum specimens at 8 to 24 hour intervals with at least 1 specimen as an early-morning specimen. Submit 5 mL to 10 mL of sputum each time in a screw-capped, sterile container. No preservative. Specimen must be delivered to laboratory promptly, ideally within 30 minutes, but at least within 1 day of collection. Specimen should be refrigerated within 1 hour of collection.
Collect specimen as follows:
1. Instruct patient to brush his/her teeth and/or rinse mouth well with water to minimize contaminating specimen with food particles, mouthwash, or oral drugs.
2. Have patient remove dentures.
3. Instruct patient to take a deep breath, hold it momentarily, then cough deeply and vigorously into container.
4. Cough induction by inhalation of a saline aerosol is acceptable. (Improperly labeled specimen, specimen in leaky container, nasal secretion, saliva, specimen in preservative, or specimen received >24 hours of collection is not acceptable.)
5. Label container with patient’s name (first and last), date and time of collection, type of specimen, and collector’s initials.
6. Maintain sterility and forward promptly.
Note: Specimen source is required.
Urine
Collect first-morning specimen on 3 to 5 consecutive days. Organisms accumulate in bladder overnight, so first-morning void provides best yield. Specimen collected at other times is dilute and is not optimal.
1. Collect an entire first-morning, random urine collection in a screw-capped, sterile container. No preservative. (Improperly labeled specimen, specimen in leaky container, 24-hour collection, or specimen in preservative is not acceptable.)
2. Label container with patient’s name (first and last), date and time of collection, type of specimen, and collector’s initials.
3. Maintain sterility and forward promptly.
Note: Specimen source is required.
Reference Values
Smear: no AFB seen
Critical value (automatic call-back): positive