Test Catalog

Test Id : CTBBL

Mycobacterial Culture, Blood

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosing mycobacteremia

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial 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
TBMP Mycobacteria Probe Ident No, (Bill Only) No
TBPB Mycobacteria Probe Ident Broth No, (Bill Only) No
LCTB Id, MTB complex Rapid PCR No, (Bill Only) No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Method Name
A short description of the method used to perform the test

Continuously Monitored Automated Broth Culture Instrument with Conventional Methods for Identification of Mycobacteria

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Mycobacterial Culture, B

Lists additional common names for a test, as an aid in searching

Acid-Fast Bacilli (AFB)

AFB (Acid-Fast Bacilli)

Bacillus, Acid-Fast

Culture, TB (Tuberculosis)

MTB (Mycobacterium tuberculosis)

Mycobacteria Culture

Mycobacterium tuberculosis (MTB)

TB (Tuberculosis)

TB (Tuberculosis) Culture

Tubercle Bacilli: Mycobacterium tuberculosis

Tuberculosis (TB)

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Specimen Type
Describes the specimen type validated for testing

Whole blood

Shipping Instructions

Specimen must be processed within 72 hours of collection.

Necessary Information

Specimen source is required.


Question ID Description Answers
Q00M0015 Specimen Source

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing


Preferred: Green top (sodium or lithium heparin)

Acceptable: SPS/Isolator System

Specimen Volume: 8 to 10 mL per culture

Collection Instructions:

1. Send specimen in original tube.

2. Isolator System/SPS tubes are acceptable, but not preferred.

3. Draw blood in an Isolator/SPS tube and send 8 mL of whole blood in the original Isolator tube.

4. Note: when sending SPS tube, it must be clearly labeled SPS. If label is obscured, sample may be cancelled, as ACD (yellow top) is not an acceptable tube type.


If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

No specimen should be rejected.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 72 hours
Refrigerated 72 hours

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosing mycobacteremia

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Mycobacteremia occurs most often in immunocompromised hosts. The majority of disseminated mycobacterial infections are due to Mycobacterium avium complex but bacteremia can also be caused by other mycobacterial species including, but not limited to, Mycobacterium tuberculosis complex, Mycobacterium kansasii, Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium scrofulaceum, Mycobacterium szulgai, and Mycobacterium xenopi.(1)


Mycobacterial blood cultures may be indicated for patients presenting with signs and symptoms of sepsis, especially fever of unknown origin.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


If positive, mycobacteria is identified.

A final negative report will be issued after 42 days of incubation.

Provides information to assist in interpretation of the test results

A positive result may support the diagnosis of mycobacteremia.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Results must be interpreted in conjunction with the patient's history and clinical picture.


A negative result does not rule out mycobacteremia. The organism may be present at quantities below the limit of detection or may be transiently present.


If Mycobacterium genavense is suspected, indicate on request form or contact laboratory. Mycobactin J (an iron supplement) will then be added to the culture to support growth.

Supportive Data

During validation of this test, a variety of mycobacteria were recovered from spiked blood specimens. These mycobacteria were Mycobacterium fortuitum, Mycobacterium intracellulare, Mycobacterium kansasii, Mycobacterium tuberculosis, and Mycobacterium xenopi. Mycobacterium genavense was recovered when the medium was supplemented with mycobactin J (an iron supplement). In addition, aerobic actinomycetes including Nocardia farcinica, Gordonia terrae, Rhodococcus equi, and Tsukamurella paurometabola were also recovered when spiked into blood. The limit of detection was determined to be less than or equal to 10(2) colony forming units (CFU)/mL for Mycobacterium fortuitum and Mycobacterium tuberculosis, 10 CFU/mL for Mycobacterium intracellulare, and 1 CFU/mL for Nocardia farcinica.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Pfyffer GE: Mycobacterium: General characteristics, laboratory detection, and staining procedures. In: Jorgensen JH, Pfaller MA, Carroll KC, et al, eds. Manual of Clinical Microbiology. 11th ed. ASM Press; 2015:536-569

2. Reimer LG: Laboratory detection of mycobacteremia. Clin Lab Med. 1994;14:99-105

Method Description
Describes how the test is performed and provides a method-specific reference

The blood is processed per the manufacturer's instructions before adding it to a VersaTREK Myco bottle and plating onto Middlebrook 7H10 agar. The agar plate is incubated at 37 degrees C with 5% to 7% carbon dioxide (CO2) for 42 days. The VersaTREK Myco bottle is incubated on the automated VersaTREK 528 instrument for 42 days. If the bottle signals as positive on the instrument, it is removed, and a smear is performed to look for acid-fast organisms. Acid-fast organisms are identified using conventional methods including nucleic acid hybridization probes, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and 16S rDNA gene sequencing.(Mirrett S, Hanson KE, Reller LB: Controlled clinical comparison of VersaTREK and BacT/ALERT blood culture systems. J Clin Microbiol. 2007 Feb;45(2):299-302; Buckwalter SP, Olson SL, Connelly BJ, et al: Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for the Identification of Mycobacterium species, Nocardia species, and Other Aerobic Actinomycetes. J Clin Microbiol. 2016 Feb;54(2):376-384. doi: 10.1128/JCM.02128-15; Hall L, Doerr KA, Wohlfiel SL, Roberts GD: Evaluation of the MicroSeq system for identification of mycobacteria by 16S ribosomal DNA sequencing and its integration into a routine clinical mycobacteriology laboratory. J Clin Microbiol. 2003 Apr;41(4):1447-1453) 

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

42 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

24 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87116-Mycobacterial Culture

87118-Id MALDI-TOF Mass Spec AFB (if appropriate)

87150-Id, Mtb Speciation, PCR (if appropriate)

87150-Mycobacteria Probe Ident, Broth(if appropriate)

87150-Mycobacteria Probe Ident, Solid(if appropriate)

87153-Mtb PZA Confirmation, pcnA sequence (if appropriate)

87153-Mycobacteria Identification by Sequencing (if appropriate)

87150- Id, MTB complex Rapid PCR (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
CTBBL Mycobacterial Culture, B 64412-0
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
CTBBL Mycobacterial Culture, B 64412-0

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports