Skin Culture, Mycobacterium

CPT CODE: 87117; 87206
TEST INFORMATION: Test includes culture and acid-fast stain (if specimen volume is adequate). Culture includes decontamination and concentration. If a mycobacterial species is isolated, the organism will be definitely identified. Susceptibility testing will be performed depending upon the isolate identification. Other isolated organisms (i.e. aerobes, yeast, etc.) may be referred for identification and/or susceptibility testing if medically indicated AND a separate culture procedure has NOT yielded the same organism(s).
TURNAROUND TIME: Smear results: 24 hours after receipt of the specimen in the laboratory. Preliminary culture reports are available after 1 week or when a mycobacterial isolate is detected. Negative cultures with negative smears will be finalized after 8 weeks. Negative cultures with positive smears will be finalized after 12 weeks. Completion of culture reports may require additional time when mycobacteria are isolated and/or susceptibility testing is performed.
SPECIAL INSTRUCTIONS: The specific anatomic site of the specimen MUST be specified on the order or the requisition.
CONTAINER TYPE: Sealed sterile container, no preservative
COLLECTION: Specimens are to be collected from a site prepared utilizing aseptic technique. The area to be sampled should first be cleansed with 70% alcohol to remove bacterial contaminants.
SPECIMEN REQUIREMENTS: Skin biopsy, subcutaneous material, surgical tissue
REJECTION CRITERIA: Inappropriate specimen container, insufficient specimen volume, specimen received in a preservative. Only three specimens per body site with negative acid-fast smears will be processed. Subsequent specimens will be rejected. Specimens from known positive patients will be accepted only once a week for culture and smear per body site.
MINIMUM VOLUME: As much as possible
HANDLING INSTRUCTIONS: Specimen should be transported as soon as possible. When transportation is delayed, refrigerate specimen.
REFERENCE RANGE: No acid-fast bacilli observed on smear or isolated in culture
LIMITATIONS OF TEST: Mycobacterium leprae CANNOT be grown in culture. A single negative smear does not rule out the presence of mycobacterial infection.
METHODOLOGY: Acid-fast smear: fluorochrome stain. Culture: inoculation of conventional culture media at two temperatures and a rapid medium for automated continuous analysis.


Mycobacterium marinum is frequently responsible for granulomatous cutaneous lesions acquired from heated swimming pools and fish tanks. Lesions similar to those seen with sporotrichosis follow lymphatics. M. fortuitum and M. chelonae complex organisms are saprophytic mycobacteria which can cause cutaneous abscesses and osteomyelitis in traumatic injury. M. ulcerans causes a chronic granulomatous skin lesion called Buruli ulcer. M. ulcerans may also be saprophytic, colonizing cutaneous ulcers associated with circulatory insufficiency and diabetes. M. ulcerans is uncommon in North America; it is most frequently isolated in Australia and Africa. M. avium complex (MAC) and M. tuberculosis may also be isolated from skin lesions. DNA probes may be incorporated to aid with more rapid identification of mycobacterial isolates. This will generate an additional charge(s). Susceptibility testing will be performed only on the first Mycobacterium isolate from each specimen type per patient. Additional susceptibilities may be performed after a period of 4 weeks for patients with suspected treatment failure. Susceptibility testing is performed routinely only for M. tuberculosis. Susceptibility testing for other Mycobacterium species is performed by special request only. The battery of drugs routinely tested will vary by isolate and/or physician request. Patients from whom M. tuberculosis is isolated in culture are reported to the City of Chicago Board of Health. This is mandated by law.



TEST SYNONYM(S):AFB Culture, Cutaneous; AFB Culture, Skin; Mycobacterium Culture; TB Culture