AFB Culture & Stain
Test Mnemonic
AFC
CPT Codes
- 87116 - QTY (1)
- 87206 - QTY (1)
- 87015 - QTY (1)
Aliases
- Acid-fast Bacilli Culture and Stain
- TB Culture and stain
- Acid Fast Bacilli
- Mycobacteria
- Nocardia
- Tuberculosis
- Mycobacterium
- Acid fast
Includes
- Test includes specimen decontamination and concentration, culture and stain for acid fast bacilli, and identification and susceptibility testing, as appropriate.
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 10 mL | Bronchoscopy specimen | Sterile container | Ambient | Larger volumes improve recovery. Collect BAL, wash, or aspirate into sputum trap or sterile cup. Volume: at least 10 mL (preferred). Place bronchial brush in sterile, leak-proof tube or cup with enough non-bacteriostatic sterile saline to cover the brush (1-10 ml). Transfer temperature is ambient. Refrigeration is preferred if transport is delayed longer than 2 hours. | |
| 10 mL | Aspirate, tracheal | Sterile container | Ambient | Larger volumes improve recovery. Refrigeration is preferred if transport is delayed longer than 2 hours. Volume 5-10 mL (preferred). | |
| 1 - 5 g | Tissue | Sterile container | Ambient | Biopsy material from the periphery of a cutaneous lesion. Tissue may be kept moist with a small amount (1-3 ml) of sterile saline. Send a separate portion for histopathology using sterile technique. Tissue in formalin is unacceptable for culture. Transport temperature is ambient. Refrigeration is preferred if transport is delayed longer than 2 hours. | |
| 5 mL | Sputum | Sterile container | Refrigerated | Sputum may be expectorated or induced. Collection of 3 sputum specimens at least 8 hours apart with at least one first morning specimen is recommended. Refrigeration is preferred if transport is delayed longer than 2 hours. Volume: 5 mL (preferred); 1 mL minimum. | |
| 10 mL | Fluid, body | Sterile container | Ambient | Aspirate pleural, pericardial, peritoneal, or synovial fluid using sterile technique after skin disinfection or during surgical procedure. Transfer fluid to sterile tube or cup. Transport temperature is ambient. Refrigeration is preferred if transport is delayed longer than 2 hours. Volume: 10-15 mL (preferred); 1 mL minimum. | |
| Unspecified | Aspirate(s) | Sterile container | Ambient | Larger volumes improve recovery. Aspirate from closed abscess to surface using sterile technique after skin disinfection. Aspirate from both the center and wall of the abscess. For open wounds remove exudate by rinsing with sterile saline. Collect specimen from margin of lesion or abscess using a syringe. If specimen volume is small, instilling a small volume of sterile, non-bacteriostatic saline into the lesion may aid collection. Transfer specimen to sterile tube or submit in syringe after removing needle and capping. Swabs are unacceptable. Refrigeration is preferred if transport is delayed longer than 2 hours. | |
| Unspecified | Skin | Sterile container | Refrigerated | Skin scraping in sterile petri dish or sterile container with blade used to obtain specimen. | |
| 5 mL | Aspirate, gastric | Sterile container | Refrigerated | Patient must be fasting. Transport to Laboratory for receipt within 4 hours of collection. If specimen not received in lab within 4 hours, neutralize with (100 mg) sodium bicarbonate (pH 7). For increased sensitivity, collect specimens on 3 consecutive days. Refrigeration is preferred if transport is delayed longer than 2 hours. Volume: 5-10 mL (preferred). | |
| 40 mL | Urine, random | Sterile container | Ambient | Submit entire first morning void in sterile container without preservative. 40 mL preferred. For increased sensitivity, collect specimens on 3 consecutive days. Twenty-four hour collections are unacceptable. Patient Preparation: Usual preparation for clean-catch mid-void urine collection. Transport temperature is ambient. Refrigeration is preferred if transport is delayed longer than 2 hours. | |
| 5 mL | Cerebrospinal fluid (CSF) | Sterile container | Ambient | Culture yield is increased with larger specimen volumes. Specimen volumes between 0.5 and 2 mL will be processed with a disclaimer. Do not refrigerate if routine bacterial culture is performed on same CSF specimen. | |
| 1 g | Stool | Sterile container | Ambient | Pass stool and collect as for bacterial culture. Submit in sterile, leak-proof container, without preservatives. Transport temperature is ambient. Refrigeration is preferred if transport is delayed longer than 2 hours. |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 24 hours |
| Refrigerated | 1 week |
| Frozen | Unacceptable |
Days Performed
Sun - Sat
Turnaround Time
7 weeks
Methodology
| Name | Description |
|---|---|
| Culture | |
| Stain | |
| DNA Sequencing | |
| Matrix-assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry |
Reference Range
| AFB Culture | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Negative for Mycobacteria Growth | |||||
| AFB Stain | |||||
| Sex | Age From | Age To | Type | Range | Range Unit |
| ~ |
Special Info
Mycobacterial culture (AFC) includes an acid-fast stain and culture for AFB on solid agar and in liquid medium. Nocardia spp. will grow from AFB cultures. Stain results are reported within 24 hours of specimen receipt. Cultures are incubated for 6 weeks; negative cultures are updated weekly. Extended incubation or special requests require consultation with a medical director. Do not put special instructions in order comments. Providers are notified of initial positive smear or culture results and any identification of M. tuberculosis. Specimen collection methods should minimize contamination with respiratory, skin or urogenital flora. If specimen transport is delayed by more than 2 hours, specimens should be refrigerated. When collecting in the outpatient setting, patients should be sent home with a pre-labeled container. Instruct patients to record collection date/time on the labeled container and refrigerate the specimen until submission. Due to the small volume collected and hydrophobicity of mycobacteria, swabs are suboptimal for recovery, and will be rejected. Exceptions require medical director approval. If a swab must be used, E swab is preferred. Both source and body site should be provided with orders. Specimens from all skin sites and those from the extremities are cultured at both 37°C and 30°C to optimize recovery of M. marinum, M. haemophilum and some rapidly growing mycobacteria. In Epic, the “Rule-out” drop down feature may be used when ordering to notify the laboratory if species with special growth requirements are in the differential. Mycobacteria and Nocardia spp. from positive cultures are identified using a combination of MALDI TOF and/or sequencing methods. Susceptibility testing is performed on all M. tuberculosis, Nocardia species and M. kansasii. Other susceptibility testing is performed on request, if clinically significant. The clarithromycin microbroth dilution test is incubated 14 days to detect phenotypic inducible resistance in rapidly growing mycobacteria. Molecular testing for erm(41) which mediates inducible resistance to clarithromycin is performed for M. abscessus species. Deletions in erm(41) prevent inducible clarithromycin resistance and are present in M. abscessus subsp. massiliense. Multiple identification procedures may be required. The following CPT codes are billed as applicable: Cepheid PCR 87556 87798, Additional stain testing 87206, MALDI-TOF 87118, Sequencing 87153, and Susceptibility Testing 87186.
Clinical Info
Culture is performed to identify infection due to mycobacteria. Negative cultures do not rule-out infection. Multiple cultures (three) are generally performed to optimize sensitivity and to help determine the clinical significance of pulmonary infection with non-tuberculous mycobacteria. Clinical presentation, radiographic findings and histopathology should be evaluated in conjunction with culture data. (PMID: 32797222). For patients in whom a diagnosis of pulmonary M. tuberculosis is in the differential, PCR (MTBRIF) is recommended on at least one respiratory specimen, and may be ordered on up to two specimens collected at least eight hours apart, including one first-morning sputum. For optimal sensitivity three cultures are recommended. (MMWR 62:41; 2013) Sensitivity of PCR for smear positive, culture positive TB is 97%; sensitivity for smear-negative, culture positive TB is 67%. (PMID 31173647) Orders for MTBRIF include culture and stain. Order MTBRIF x2 and AFB culture (AFC) x1 for diagnosis of M. tuberculosis. PCR may be added to AFB cultures previously submitted to the laboratory by calling Lab Client Services and requesting (PCR component) LAB1042. Rifampin resistance detection requires confirmatory sequencing and correlation with in vitro susceptibility test results.