Test ID: CTBBL
Mycobacterial Culture, Blood
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosing mycobacteremia
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
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
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)
82443-CTBBL
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen must arrive within 48 hours of draw.
Container/Tube:
Preferred: Green top (heparin)
Acceptable: Isolator tube
Specimen Volume: 10 mL per culture
Collection Instructions: Send specimen in original tube.
Additional Information: Specimen source is required.
Forms: If not ordering electronically, submit a Microbiology Request Form (Supply T244) with the specimen.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Ambient (preferred) | 48 hours |
| Refrigerated | 48 hours |
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.
Negative
If positive, mycobacteria is identified.
A final negative report will be issued after 60 days of incubation.
Interpretation Provides information to assist in interpretation of the test results
A positive result may support the diagnosis of mycobacteremia.
Cautions 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 because false-positive results may occur due to specimen contamination.
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
Mayo isolation rates of mycobacteria from 1995–1998 from 172,928 blood cultures was 0.01% (20 positive cultures from 12 patients).
During validation of this test at Mayo, a variety of mycobacteria were recovered from artificially 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 ≤10(2) colony forming units (CFU)/mL for Mycobacterium fortuitum and Mycobacterium tuberculosis, 10(1) CFU/mL for Mycobacterium intracellulare and 1 CFU/mL for Nocardia farcinica.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Pfyffer GE:Mycobacterium:General characteristics, laboratory detection, and staining procedures. In Manual of Clinical Microbiology. 9th edition. Edited by PR Murray, EJ Baron, JH Jorgensen, et al. ASM Press, Washington DC, 2007, pp 543-572
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
Blood is drawn in a heparin tube and must be transported to the laboratory (ambient) within 48 hours. Five milliliters of blood is then transferred to a conical 50-mL centrifuge tube and sterile, distilled water is added to a final volume of 40 mL to lyse the cells. The tube is centrifuged at 3,000 x g for 20 minutes and the supernatant is decanted. Two milliliters of sterile phosphate buffer is added to resuspend the sediment, 1 mL of the suspension is added to a VersaTREK Myco bottle and 0.5 mL is plated onto 7H10 agar. The agar plate is incubated at 37 degrees C with 5% to 7% carbon dioxide (CO[2]) for 42 days. The VersaTREK Myco bottle is incubated on the automated VersaTREK 528 instrument for 42 days. The instrument continuously monitors headspace pressure changes within the bottle, which correspond to gas production or consumption due to microbial growth. After a 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 or 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;45:299-302; 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;41:1447-1453)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
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's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
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 Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
Mycobacterial Culture
87116
Mycobacteria Identification by Sequencing
87153 (if appropriate)
Mycobacteria Probe Ident, Solid
87150 (if appropriate)
Mycobacteria Probe Ident, Broth
87150 (if appropriate)
Ident, M. chelonae and M. abscessus, PCR
87149 (if appropriate)
Tissue Processing
87176 (if appropriate)
Mycobacteria Culture, Concentration
87015 (if appropriate)
Susc, Mtb MOP, 1 drug
87190 (if appropriate)
Mtb PZA Confirmation, pcnA sequence
87153 (if appropriate)
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| CTBBL | Mycobacterial Culture, B | In Process |
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