MALDI-TOF MS mycobacterial identification

TEST DESCRIPTION

Identification of mycobacteria species using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS). MALDI-TOF MS technology analyzes the proteins, mainly ribosomal proteins, of a microorganism. The instrument converts the microorganism’s proteins into a protein profile or fingerprint. This protein profile is compared to profiles of microorganisms in a reference database, and the identity of a mycobacterium is confirmed when a close match is found to a reference profile.

Methodology

MALDI-TOF mass spectrometry

TEST FREQUENCY & RESULT AVAILABILITY

Performed weekly. Results are typically available within 4 weeks after the mycobacterium has been isolated, but may take longer because significant mycobacterial growth is needed for testing.

ACCEPTABLE SPECIMEN TYPES AND COLLECTION

An acid-fast bacilli (AFB) isolate submitted on solid media (e.g., Lowenstein Jensen, 7H10)
Patient specimens submitted for AFB (mycobacteria) culture will be eligible and reflexed for testing once a microorganism has been isolated from the specimen

SPECIMEN STORAGE

For AFB isolates submitted on solid media, store and transport at room temperature (17–25 °C/63 °F–77 °F) . All culture containers should be taped securely and double bagged when submitted.

Note: If Mycobacterium tuberculosis is suspected, Category A (UN2814) packaging is required. Please contact the laboratory if Category A shipping supplies are needed.

SPECIMEN TRANSPORT

Shipping conditions should follow the temperature and time requirements outlined above.

REJECTION CRITERIA

AFB isolates that are non-viable
AFB isolates that arrive in culture containers that are damaged during transit or are not properly labeled with patient identifiers

CODES

CPT: 87118
LOINC: 76346-6
Test code: 3660

TEST FEE

Refer to the current fee schedule.