87116

Culture, tubercle or other acid-fast bacilli (eg, TB, mycobacteria) any source, with isolation and presumptive identification of isolates

Current Procedural Terminology (CPT) code 87116 represents the laboratory procedure for the culture and presumptive identification of tubercle bacilli (Mycobacterium tuberculosis complex) and other acid-fast bacilli (AFB), commonly referred to as non-tuberculous mycobacteria (NTM). This code covers the isolation of the organism from various clinical specimens, such as sputum, bronchial washings, pleural fluid, tissue biopsies, cerebrospinal fluid (CSF), or blood. Because mycobacteria are typically slow-growing organisms, their cultivation requires specialized microbiological techniques distinct from routine bacterial cultures. The laboratory process begins with specimen preparation, which is a critical step, especially for non-sterile specimens like sputum. The sample undergoes digestion and decontamination, typically utilizing an N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) method. This process liquefies the organic debris and kills rapidly growing normal respiratory flora that would otherwise overgrow and mask the slower-growing mycobacteria. Following decontamination, the specimen is concentrated via high-speed centrifugation to maximize the yield of organisms. The concentrated sediment is then inoculated into both liquid media (such as the Mycobacteria Growth Indicator Tube, or MGIT) and solid media (such as Lowenstein-Jensen or Middlebrook agar). Liquid media systems utilize automated continuous monitoring to detect early growth through fluorescence or oxygen consumption, often yielding positive results within one to three weeks. Solid media are incubated and visually inspected weekly for up to six to eight weeks. Upon detecting growth, the laboratory technician performs an acid-fast stain (e.g., Ziehl-Neelsen or fluorochrome) on the culture isolate to confirm the presence of acid-fast bacilli. Presumptive identification is subsequently established based on the organism's growth rate, colony morphology, and pigmentation (chromogenicity). It is important to note that CPT 87116 includes only the culture and this initial, presumptive identification. Further definitive identification to the species level, utilizing molecular probes, mass spectrometry, or extensive biochemical testing, is reported separately using appropriate definitive identification codes.

Clinical Indications

  • Suspected pulmonary or extrapulmonary Mycobacterium tuberculosis infection.
  • Suspected non-tuberculous mycobacterial (NTM) infection (e.g., Mycobacterium avium complex).
  • Chronic, unexplained cough, often accompanied by hemoptysis.
  • Unexplained constitutional symptoms including night sweats, fever, and abnormal weight loss.
  • Radiographic findings suggestive of mycobacterial disease, such as upper lobe cavitary lesions, granulomas, or miliary patterns.
  • Monitoring the bacteriological response to anti-mycobacterial therapy in patients with known tuberculosis.
  • Evaluating patients with human immunodeficiency virus (HIV) or other immunocompromising conditions presenting with atypical respiratory symptoms.

Procedure Steps

  1. Receive and accession the clinical specimen (e.g., sputum, bronchoalveolar lavage, tissue) into the laboratory information system.
  2. Perform digestion and decontamination of non-sterile specimens using chemical agents (e.g., NALC-NaOH) to eliminate normal flora and liquefy mucus.
  3. Neutralize the chemical agents to prevent toxicity to the mycobacteria.
  4. Concentrate the specimen by high-speed centrifugation to pellet any mycobacteria present.
  5. Inoculate the concentrated sediment into selective liquid media (e.g., MGIT broth) and onto solid media (e.g., Lowenstein-Jensen or Middlebrook 7H10/7H11 agar).
  6. Incubate the inoculated media in specific environmental conditions (typically 37 degrees Celsius; sometimes lower temperatures are used for skin/superficial lesions).
  7. Monitor liquid cultures continuously via automated systems for signs of growth, and visually inspect solid media weekly for up to 6 to 8 weeks.
  8. Perform an acid-fast bacillus (AFB) stain on any growth detected to confirm the isolate is an acid-fast organism.
  9. Perform presumptive identification based on growth characteristics such as days to growth (rapid vs. slow), colony morphology, and pigmentation (photochromogen, scotochromogen, or nonchromogen).
  10. Report the presumptive identification results to the ordering physician.

Coding Guidelines

  • Report 87116 once per specimen submitted for mycobacterial culture.
  • Do not report 87116 for routine bacterial cultures; use 87070 or equivalent.
  • Code 87116 includes presumptive identification. For definitive identification to the species level (e.g., using nucleic acid probes, MALDI-TOF, or extensive biochemicals), report the appropriate definitive identification code (e.g., 87118, 87149) in addition to 87116.
  • If a direct acid-fast smear is performed directly on the primary source specimen (not the culture isolate), report 87206 separately.
  • If antimicrobial susceptibility testing is performed on the isolated mycobacteria, report 87186 or 87188 as appropriate.
  • When multiple distinct specimens (e.g., three separate sputum samples collected on different days) are submitted, 87116 may be billed for each discrete specimen.

Associated ICD-10 Codes