Culture of Donor Bone Tissue
Test Code
AFB8
Description
This test is a culture for acid fast bacilli (AFB) in donor bone tissue. This research use only test is used for identifying contamination of donor bone matrices with mycobacteria, especially M. tuberculosis.
Donor bone specimen is inoculated onto multiple media types (including solid and liquid media) followed by monitoring for eight weeks. Growth of any mycobacteria is reported, and organisms are identified as M. tuberculosis or other nontuberculous mycobacteria (NTM) using first-line assays (i.e. no sequencing is performed for a higher-level identification). Note that a smear from the donor sample is not performed.
Collect
- Donor bone tissue may include bone marrow, "bone slurry" or "viable bone matrix". Bone slurries are typically processed minimally by the donor testing facility and may contain blood. Viable bone matrix is typically a processed specimen that is ready for transplant and therefore should be sterile and contain minimal blood.
- Specimens should collected and ground into a homogenous matrix.
- Submit a minimum of 1 mL of tissue. Each submitted sample will be treated independently.
Unacceptable Conditions
- Donor samples without two unique identifiers will be rejected.
- Donor samples that are received thawed will be rejected.
Stability
Ambient or refrigerated (up to 72 hours), frozen (indefinite)
Notes
AFB smear is not performed.
Performed
Typically all days
Methodology
Samples are cultured on solid and liquid media in parallel. No smear is performed and samples are not digested or decontaminated.
Liquid media is incubated for up to 6 weeks. Solid media are incubated for an additional two weeks; a supplementary report will be released at 8 weeks.
Line probe assays are used to identify mycobacteria as M. tuberculosis, commonly seen NTM (e.g. M. avium, M. intracellulare subsp. intracellulare, M. intracellulare subsp. chimaera, M. abscessus subspecies, and M. chelonae), or as other mycobacteria. See AFB4 for further details.
Turnaround Time
- Solid media are read at 1, 3, 6 and 8 weeks; liquid media is read continually.
- If negative, a "final" report for the AFB culture is issued at 6 weeks, but a supplementary report will be issued at 8 weeks
- Positive media are reported at the time growth is detected. Mycobacterial identification is reported within 3 days to 2 weeks.
Department
Infectious Disease Laboratory, Mycobacteriology
Synonyms
Donor tissue, viable bone matrix
Study Offerings
RUO
Related Tests
VBMTB (Molecular detection of M. tuberculosis in donor tissue)
Reference Interval
Negative for acid fast bacilli.
Interpretation
| Test | Interpretations |
|---|---|
| AFB Culture | Negative cultures are reported as negative for growth. Positive cultures are reported as organisms recovered with a colony count where possible (CFU/mL). |
| AFB Identification | Organisms are identified using line probe assays in order to differentiate M. tuberculosis from other common NTM |
CPT Code
N/A, this is not a clinical test.
Also, note that this is a test algorithm. First, culture is performed. If an organism is recovered, a reflex identification test will be ordered. The identification method used will depend on the organism.
| Method | Billing codes | When is this applied? | |
|---|---|---|---|
| AFB Culture | Culture | CXAFB2 | All samples |
| AFB Identification |
PCR/MALDI-TOF mass Spectrometry | MASID (1st organism), MASI2 (2nd organism), MASI3 (3rd organism) |
If appropriate organisms are recovered |
| Line probe assay | NTMID (1st organism), NTMD2 (2nd organism), NTMD3 (3rd organism) |
If appropriate NTM organisms are recovered | |
| Line probe assay | MTB7T | If the appropriate MTBC organism is recovered. |
Billing Codes
VBMTBNew York Approved
Other
New York Approval Comments
RUO testing
FDA
Other
FDA Approval Comments
Performed as Research Use Only