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HelpTest Code CTB Mycobacteria and Nocardia Culture, Varies
Reporting Name
Mycobacterial CultureUseful For
Detection and identification of Mycobacterium species, Nocardia species, and other aerobic actinomycetes
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
VariesNecessary Information
1. Specimen source is required.
2. Alert the laboratory if Mycobacterium genavense is suspected, as this species requires addition of mycobactin J to the culture medium for optimal growth and recovery.
Specimen Required
Submit only 1 of the following specimens:
Specimen Type: Body fluid
Container/Tube: Sterile container
Specimen Volume: 1.5 mL
Specimen Type: Bone marrow
Container/Tube: Sterile container, or green top (lithium or sodium heparin)
Specimen Volume: Entire collection
Specimen Type: Gastric washing
Container/Tube: Sterile container
Specimen Volume: 10 mL
Collection Instructions: Neutralize specimen within 4 hours of collection with 100 mg of sodium carbonate per 5 to 10 mL of gastric wash.
Specimen Type: Respiratory
Sources: Bronchoalveolar lavage fluid, bronchial washing, sputum
Container/Tube: Sterile container
Specimen Volume: 3 mL
Collection Instructions:
1. Collect 3 respiratory specimens for acid-fast smears and culture in patients with clinical and chest X-ray findings compatible with tuberculosis.
2. These 3 specimens should be collected at 8 to 24-hour intervals (24 hours when possible) and should include at least 1 first-morning specimen.
Specimen Type: Stool
Supplies: Stool Collection Kit, Random (T635)
Container/Tube: Sterile container
Specimen Volume: 5 to 10 g
Specimen Type: Tissue
Container/Tube: Sterile container
Specimen Volume: 5 to 10 mm
Collection Instructions: Collect a fresh tissue specimen.
Specimen Type: Urine
Container/Tube: Sterile container
Specimen Volume: 20 to 50 mL
Collection Instructions: Collect a random urine specimen.
Fresh tissue or body fluid is the preferred specimen type instead of a swab specimen. Recovery of mycobacteria from swabs is generally very low yield.
Specimen Type: Swab
Sources: Wound, tissue, or body fluid
Container/Tube: Culture transport swab (noncharcoal) culturette, or Eswab
Specimen Volume: Adequate specimen
Collection Instructions:
1. Before collecting specimen, wipe away any excessive amount of secretion and discharge, if appropriate.
2. Obtain secretions or fluid from source with sterile swab.
3. If smear and culture are requested or both a bacterial culture and mycobacterial culture are requested, collect a second swab to maximize test sensitivity.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Refrigerated (preferred) | 7 days |
| Ambient | 7 days |
Reference Values
Negative
Day(s) Performed
Monday through Sunday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
87116-Mycobacterial Culture
87015-Mycobacteria Culture, Concentration (if appropriate)
87118-Id MALDI-TOF Mass Spec AFB (if appropriate)
87150-Id, Mtb Speciation, PCR (if appropriate)
87153-Mycobacteria Identification by Sequencing (if appropriate)
87176-Tissue Processing (if appropriate)
87150- Id, MTB complex Rapid PCR (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CTB | Mycobacterial Culture | 543-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CTB | Mycobacterial Culture | 543-9 |
Testing Algorithm
When this test is ordered, a reflex test may be performed at an additional charge.
The following algorithms are available:
Special Instructions
Clinical Information
Mycobacteria species are responsible for significant morbidity and mortality in both immunocompromised and immunocompetent hosts. Mycobacterium tuberculosis is the causative agent of tuberculosis, and it kills nearly 2 million people in the world each year. Nontuberculous mycobacteria such as Mycobacterium avium complex and Mycobacterium abscessus cause a variety of infections (eg, respiratory, skin, and soft tissue) and are important to detect and correctly identify in order to aid in clinical decision making. There are approximately 200 recognized species of mycobacteria and identification of these organisms to the species level is often required to help guide appropriate therapy. Although there are direct detection methods available for M tuberculosis, growth of the organism on culture media is still necessary to allow for antimicrobial susceptibility testing. At this time, direct molecular detection methods are lacking for the nontuberculous mycobacteria and growth in culture is critical for identification and antimicrobial susceptibility testing.
Nocardia species and other aerobic actinomycetes (eg, Tsukamurella species, Gordonia species, Rhodococcus species) are also important causes of disease and isolation on culture media is important to facilitate identification and antimicrobial susceptibility testing. Nocardia and the other aerobic actinomycetes grow well on mycobacterial medium, and therefore, ordering a mycobacterial culture is recommended when infection with this group of organisms is suspected.
Interpretation
A final negative report is issued after 42 days of incubation.
Positive cultures are reported as soon as detected.
Method Description
The BACTEC MGIT 960 System is a broth system designed for the rapid detection of mycobacteria in clinical specimens. Mycobacteria Growth Indicator Tubes (MGIT) are incubated for up to 42 days and growth is evaluated with mycobacteria identified as soon as a MGIT signals positive on the instrument.
In addition to the MGIT tube, Middlebrook 7H10/7H10S agar biplates are inoculated and incubated at 37° C for 42 days. Growth from positive MGITs or agar plates is identified using a variety of techniques as appropriate including rapid polymerase chain reaction, matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry, or 500 basepair 16S rRNA gene sequencing.
The Mycobacterium tuberculosis complex will be identified to the species level upon request using rapid polymerase chain reaction.(Martin I, Pfyffer GE, Parrish N: Mycobacterium: General characteristics, laboratory detection and staining procedures. In: Carroll KC, Pfaller MA, Landry ML, et al, eds. Manual of Clinical Microbiology. 12th ed. Vol 1. ASM Press; 2019:558-575; Halse TA, Escuyer VE, Musser KA: Evaluation of a single tube multiplex real-time PCR for differentiation of the Mycobacterium tuberculosis complex in clinical specimens. J Clin Microbiol. 2011;49[7]:2562-2567. doi:10.1128/JCM.00467-11)
Reject Due To
| Blood or fixed tissue Specimen in viral transport medium (including but not limited to M4, M5, BD viral transport media, thioglycolate broth) Saliva Swab sources of respiratory fluids (eg, sputum) Swab sources of nasal, sinus, ear, mouth, throat, or scalp Wood shaft or charcoal swab Petri dish |
Reject |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| ISMY | ID by 16S Sequencing | No, (Bill Only) | No |
| RMALM | Id MALDI-TOF Mass Spec AFB | No, (Bill Only) | No |
| RTBSP | Id, Mtb Speciation, PCR | No, (Bill Only) | No |
| TBT | Concentration, Mycobacteria | No, (Bill Only) | No |
| TISSR | Tissue Processing | No, (Bill Only) | No |
| LCTB | Id, MTB complex Rapid PCR | No, (Bill Only) | No |
Specimen Minimum Volume
See Specimen Required
Method Name
Automated Detection of Positive Cultures followed by Organism Identification /DNA Sequencing/Matrix Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
Forms
If not ordering electronically, complete, print, and send 1 of the following:
-Microbiology Test Request (T244)
-General Request (T239)