Test Catalog

Interpretive Handbook

Test 80278 :
Culture Referred for Identification, Mycobacterium and Nocardia

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

There are over 170 recognized species of mycobacteria and more than 100 Nocardia species. Many of these species are human pathogens and, therefore, identification to the species level is important to help guide patient care. In addition, there are other aerobic actinomycete genera that can be human pathogens including, but not limited to, Tsukamurella, Rhodococcus, and Gordonia species.


Nucleic acid hybridization probes are utilized that identify specific ribosomal RNA sequences of Mycobacterium tuberculosis complex, Mycobacterium avium complex, and Mycobacterium gordonae. Other Mycobacteria species, Nocardia species and other aerobic actinomycete genera are identified using MALDI-TOF mass spectrometry or nucleic acid sequencing of a 500-base pair region of the 16S ribosomal RNA gene.

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

Rapid identification to the species level for Mycobacterium species, Nocardia species, and other aerobic actinomycete genera and species from pure culture isolates

Interpretation Provides information to assist in interpretation of the test results

Organisms growing in pure culture are identified to the species level whenever possible.

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

If the organism is received in mixed culture or contaminated, the report may be delayed or identification may not be possible.

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.

Not applicable

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Pfyffer GE, Palicova F: Mycobacterium: general characteristics; laboratory detection, and staining procedures. In Manual of Clinical Microbiology. 10th edition, Vol 1. Edited by J Versalovic, KC Carroll, G Funke, et al. Washington DC, ASM Press. 2011 pp 472-502

2. 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 July;49(7):2562-2567, doi: 10.1128/JCM.00467-11

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