Please Remove Adblock
Adverts are the main source of Revenue for DoveMed. Please remove adblock to help us create the best medical content found on the Internet.

Molecular Testing for Atypical Mycobacterial Infections

Last updated July 27, 2019

Approved by: Krish Tangella MD, MBA, FCAP

Molecular Testing for Atypical Mycobacterial Infections is based on identifying specific stretches of DNA sequences unique to several species of Mycobacterium, which do not cause tuberculosis.

What are the other Names for this Test? (Equivalent Terms)

  • Gene Mutation Analysis for Atypical Mycobacterial Infections
  • Test for Molecular Diagnosis of Atypical Mycobacterial Infections

What is Molecular Testing for Atypical Mycobacterial Infections? (Background Information)

  • Molecular Testing for Atypical Mycobacterial Infections is based on identifying specific stretches of DNA sequences unique to several species of Mycobacterium, which do not cause tuberculosis
  • The lab test results may be useful in identifying the specific organism causing the infection, to ensure uninfected status, to differentiate between different disease-causing microbes, and to confirm a preliminary diagnosis
  • The test results may also be useful in conducting further lab tests to identify the sensitivity of Mycobatcerium spp. to anti-microbial agents, so that effective treatment can be undertaken
  • Atypical mycobacterial infection is any infection caused by a species of mycobacteria that does not result in classical tuberculosis
  • The species of mycobacterium that can cause atypical mycobacterial infection include:
    • Mycobacterium avium-intracellulare
    • Mycobacterium kansasii
    • Mycobacterium marinum
    • Mycobacterium ulcerans
    • Mycobacterium chelonae
    • Mycobacterium fortuitum
    • Mycobacterium abscessus
  • Any individual may develop atypical mycobacterial infections; although, the elderly and those with certain pre-existing conditions and compromised immune systems, are at the highest risk for developing the same
  • Infection by Mycobacterium spp. (which do not cause tuberculosis) can be initiated when an individual comes into contact with the pathogen either through inhalation, or via cuts, abrasions, and wounds on skin
  • Signs and symptoms of the infection vary, depending on the type of species causing the infection. These may include cough, shortness of breath, skin lesions, and swollen lymph nodes

Molecular testing for infectious organisms (viruses, bacteria, fungi, and parasites) can be performed using a variety of methods. Some of these methods include:

  • In situ hybridization techniques, such as fluorescence in situ hybridization (FISH)
  • Immunohistochemistry (IHC)
  • 16S rRNA for bacterial pathogens
  • Branch DNA (bDNA) assays
  • Hybrid capture assay
  • Nucleic acid amplification tests (NAATs), such as species-specific polymerase chain reaction (PCR), real-rime PCR
  • Transcription mediated amplification
  • Next-generation sequencing (NGS)
  • Reverse hybridization
  • Comparative genomic hybridization (CGH)
  • Whole genome sequencing
  • Flow cytometric assays with specific microbeads to detect pathogens
  • mRNA analysis
  • Nucleic acid arrays
  • Mass spectrometric analysis

Note: There may be limitations to the testing due to the method being used. Consultation with your healthcare provider will help in determining the right test and right molecular method, based on individual circumstances.

What are the Clinical Indications for performing the Molecular Testing for Atypical Mycobacterial Infections Test?

Molecular Testing for Atypical Mycobacterial Infection is undertaken in the following situations:

  • To assist in or confirm, the initial diagnosis of atypical mycobacterial infection
  • To distinguish between pathogens that produce similar symptoms
  • To eliminate suspected pathogens
  • To help in determining treatment options

How is the Specimen Collected for Molecular Testing for Atypical Mycobacterial Infections?

Following is the specimen collection process for Molecular Testing for Atypical Mycobacterial Infections:

The specimen sample requirements may vary from lab to lab. Hence, it is important to contact the testing lab for exact specimen requirements, before initiating the testing process.

Sample on which the test is performed may include:

  • Peripheral blood in individuals showing signs and symptoms suspected of atypical mycobacterial infection
  • Blood or tissue sample from individuals who are blood or organ donors
  • Body fluids such as saliva, urine, cerebrospinal fluid (CSF), pleural fluid, ascites fluid, drainage from abscesses and lesions, sputum, phlegm, and mucus (from nose, throat and genitals)
  • Specimen obtained through swaps from different sites in the body, such as nasal, throat, corneal, vaginal, rectal and from lesions
  • Stool
  • Fresh tissue from biopsy
  • Fresh tissue from autopsy sample
  • Fresh tissue from fetal demise
  • Products of conception sample from aborted pregnancy

Important Information:

Turnaround time for test results

  • Depending on the location of testing, it may take anywhere from 3 days to 3 weeks from the time of sample collection, to obtain test results

Sample storage information

  • Many hospitals preserve the paraffin blocks for at least 7 years. In general, older paraffin blocks (over 5 years) may affect the detection of specific mutations, due to degradation of the tissue specimen over time

Cost of Molecular Testing for Atypical Mycobacterial Infections:

  • The cost of the test procedure depends on a variety of factors, such as the type of your health insurance, annual deductibles, co-pay requirements, whether your healthcare provider/facility is in-network or out-of-network of your insurance company 
  • In many cases, an estimate may be provided before the test is conducted. The final amount may depend upon the findings during the test procedure and post-operative care, if required

What is the Significance of the Molecular Testing for Atypical Mycobacterial Infections Result?

The significance of Molecular Testing for Atypical Mycobacterial Infections is explained below:

  • A positive test result helps aid, and in some cases, confirm the presence of a specific pathogen
  • The test results can help in the following manner:
    • Ensure that an individual does not have an infection – as part of a routine screening procedure
    • Ensure that prospective donors do not have an infection that can be passed on to the recipients
    • Identify the pathogen in an individual suffering from an active infection
    • Exclude other conditions presenting with similar signs and symptoms
    • Make treatment decisions
    • Determine the prognosis of an affected individual

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • Many laboratories may not have the capability to perform molecular diagnostic tests. Only highly-specialized labs with advanced facilities and testing procedures may offer these tests
  • Atypical mycobacterial infection is also known as, or is closely-related to the medical condition “non-tuberculous mycobacterial infection”

Certain medications may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid any possibility of a misdiagnosis.

Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: July 17, 2017
Last updated: July 27, 2019