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22159 Acid Fast Stain

Acid Fast Stain
Test Code: AFST
Synonyms/Keywords
​Mycobacterium Stain, Smear, Acid Fast, AFB Smear Only
Useful For
​Presumptive diagnosis of Mycobacterium species in direct specimens.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​
Any
(except blood and bone marrow)​
Sterile, leakproof container (e.g. Sage container) ​ ESwab™, or other Amies medium based swab

5-10 mL​

1 swab, ESwab

1 mL fluids and secretions
0.5 g tissues
Collection Processing Instructions

Specimens should be delivered to the microbiology laboratory as soon as possible. Culture of specimens older than 24 hours may lead to a reduction in recovery of microorganisms. Do not freeze specimens at -20C, or in a frost-free freezer. Specimens should be collected in sterile leakproof containers without preservatives. A sterile anticoagulant such as heparin or SPS may be used in collection tubes to prevent clots in body fluids. Swab-collected specimens and fecal specimens are NOT recommended.

Swabs:

  • ESwab: collect one swab for Gram stain, aerobic and anaerobic cultures, and an additional swab for each additional culture type or stain (e.g. fungus or mycobacteria).
  • Other Amies medium swab types: collect one swab for every culture and stain to be ordered.

See ESwab collection video for more information

For sputum, three samples are recommended (one early morning from deep cough or expectorated sputa induced by aerosolization) eight to twelve hours apart. For urine, three specimens, one per day for three consecutive days are recommended. For gastric lavage, three early morning specimens collected on separate days are recommended. Specimens must arrive in laboratory within 4 hours. Volumes >15 mL will NOT be accepted. For blood and bone marrow AFB culture, see CULTURE, AFB, BLOOD.

Specimen Stability Information
Specimen Type Temperature Time
CSF​ Room temperature​ NA​
All other specimen types​ Room temperature <= 4 hours
​Refrigerate > 4 hours
Rejection Criteria
Pooled sputum or urine
Specimens older than 4 days​
Dried swabs or tissues​
Specimens submitted in formalin or other preservatives​
Gastric lavage specimens >4 hours old or >15mL in volume​
Leaking specimens
​Specimens > 15 mL
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Friday​ 1 day​ ​​Fluorescent Microscopy
Test Information
The AFB culture includes a smear exam.  Microscopic examinations are less sensitive than culture for mycobacteria and do not yield information concerning the viability of observed organisms.
 
Rapid growing Mycobacterium species may exhibit a negative smear result. 
 
The mycobacterial load in a clinical specimen may be low. Specimens with less than the recommended volumes may therefore lead to a false negative result.​
 
‘ESwab’ is a trademark of Copan Diagnostics.
Reference Range Information
Performing Location Reference Range
All Performing Sites​ Concentrated/unconcentrated specimen negative for acid-fast bacilli​
See Critical Value List for list of current critical values. ​
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
87206​ ​Fluorescent/acid fast stain
Synonyms/Keywords
​Mycobacterium Stain, Smear, Acid Fast, AFB Smear Only
Ordering Applications
Ordering Application Description
​Centricity ​Stain AFB
​Cerner ​Acid Fast Bacilli Smear
​COM ​Culture, AFB Smear Only
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​
Any
(except blood and bone marrow)​
Sterile, leakproof container (e.g. Sage container) ​ ESwab™, or other Amies medium based swab

5-10 mL​

1 swab, ESwab

1 mL fluids and secretions
0.5 g tissues
Collection Processing

Specimens should be delivered to the microbiology laboratory as soon as possible. Culture of specimens older than 24 hours may lead to a reduction in recovery of microorganisms. Do not freeze specimens at -20C, or in a frost-free freezer. Specimens should be collected in sterile leakproof containers without preservatives. A sterile anticoagulant such as heparin or SPS may be used in collection tubes to prevent clots in body fluids. Swab-collected specimens and fecal specimens are NOT recommended.

Swabs:

  • ESwab: collect one swab for Gram stain, aerobic and anaerobic cultures, and an additional swab for each additional culture type or stain (e.g. fungus or mycobacteria).
  • Other Amies medium swab types: collect one swab for every culture and stain to be ordered.

See ESwab collection video for more information

For sputum, three samples are recommended (one early morning from deep cough or expectorated sputa induced by aerosolization) eight to twelve hours apart. For urine, three specimens, one per day for three consecutive days are recommended. For gastric lavage, three early morning specimens collected on separate days are recommended. Specimens must arrive in laboratory within 4 hours. Volumes >15 mL will NOT be accepted. For blood and bone marrow AFB culture, see CULTURE, AFB, BLOOD.

Specimen Stability Information
Specimen Type Temperature Time
CSF​ Room temperature​ NA​
All other specimen types​ Room temperature <= 4 hours
​Refrigerate > 4 hours
Rejection Criteria
Pooled sputum or urine
Specimens older than 4 days​
Dried swabs or tissues​
Specimens submitted in formalin or other preservatives​
Gastric lavage specimens >4 hours old or >15mL in volume​
Leaking specimens
​Specimens > 15 mL
Useful For
​Presumptive diagnosis of Mycobacterium species in direct specimens.
Reference Range Information
Performing Location Reference Range
All Performing Sites​ Concentrated/unconcentrated specimen negative for acid-fast bacilli​
See Critical Value List for list of current critical values. ​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Friday​ 1 day​ ​​Fluorescent Microscopy
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
87206​ ​Fluorescent/acid fast stain
For most current information refer to the Marshfield Laboratory online reference manual.