Clinical Laboratory Guide to Services - Minnesota Dept. of Health

The Clinical Guide to Services is a comprehensive reference guide of testing services, shipping information and submission requirements. Efforts have been made to be concise and current with all information, but as testing procedures and regulations change, some information may not be current. Many of these tests are only available with prior approval from MDH. It is impossible to address all situations in this guide, so please contact us with any questions.

Specimen Requirements for Acid Fast Bacilli (AFB)

Back to Agent: Mycobacterium spp.

AFB Specimen Requirements Chart Printable Version: (PDF: 2 pages/ 156KB)

Specimen Type
Transport/Storage Temperature
Rejection Criteria
Abscess – cellulitis, eye exudate, skin lesion Optimal volume = as much as possible.
Remove surface exudate by wiping with sterile saline or 70% alcohol.  Collect fluid abscess material with syringe. For open lesions/abscesses, aspirate material from under the margin of the lesion/abscess.
Refrigerate - Formalin or other preservatives
- Swab
Blood Optimal volume = 10 mL
Aseptically collect whole blood in sodium polyanethol sulfonate (SPS – yellow top), or heparin (green top) collector tube.
Room temperature Clotted blood
-EDTA (purple top)
-ACD (yellow top - acid citrate dextrose)
- < 5 mL adults
- < 1 mL child
Body Fluids (pleural, pericardial, peritoneal, paracentesis, thoracentesis, synovial, etc.) Optimal volume = 15 mL
Collect aseptically.
For extremely bloody specimens use an SPS (yellow top) or heparin (green top) blood collection tube.
Refrigerate - < 10 mL adult
- < 1 mL pediatric
-Synovial fluid < 1ml
Bone Marrow Optimal volume = 10 mL
Aseptically collect bone marrow in sodium polyanethol sulfonate (SPS – yellow top) or heparin (green top). Mix contents after collection.
Room temperature -EDTA (purple top)
-ACD (yellow top - acid citrate dextrose)
- < 1 mL
Bronchoalveolar lavage, bronchial washings, brushings, endotracheal and  transtracheal aspirates >Optimal volume = 5 mL or more
Place bronchial brushing in sterile container with up to 5 mL sterile saline.>
Refrigerate - < 3 mL adult
- < 1 mL child
Cerebral Spinal Fluid (CSF) Optimal volume = 10 mL Refrigerate - < 2 mL  
Gastric Aspirate/Lavage Fluid Optimal volume = < 15 mL in 100 mg sodium carbonate – adjust to neutral pH.
Collect in early morning before patient eats and while they are still in bed. Perform lavage with 25-50 mL of chilled, sterile, distilled water. 1 specimen/day on 3 consecutive days.
Room temperature -Specimen that has not been neutralized.
-Multiple specimens taken from same day
Sputum Optimal volume = 5 - 10 mL
Early-morning specimen from deep, productive cough.
Expectorated sputum: instruct patient as to difference between saliva and sputum.  Have patient rinse mouth with water before collecting sputum to minimize contamination with food, mouthwash, oral drugs, etc.
Induced sputum: use sterile hypertonic saline.  Indicate on request if specimen is induced, as these watery specimens resemble saliva.
Refrigerate -24 hour pooled specimens
-Multiple specimens taken from same day that are < 8 hours apart
- < 3 mL
Stool Optimal volume = > 1 gram Refrigerate - <1 gram
- Swab
Stool cultures for mycobacteria are discouraged
Tissue biopsy -Lymph node Optimal volume = as much as possible
Collect aseptically during surgery or cutaneous biopsy procedure. Add 2-3 mL of sterile saline for transport
Refrigerate -Formalin or any other preservative
- Swab
Urine Optimal volume = 40 mL
First morning specimen is preferred.
Refrigerate -24-hour pooled
-Multiple specimens from one day
-Any preservative
- < 10 mL adult
- <5 mL child>

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Specimen Requirements for Mycobacterium

Specimen Type
Specimen Requirements
Rejection Criteria
Agar slant (LJ, 7H11, or other), plate Pure culture, visible growth. Screw cap tubes are preferred, but properly transported plates will be accepted if tubes are not available. 1. Contaminated
2. Liquefied
3. Broken in transit
4. No visible growth
Roche Sepitcheck™ Vials, MGIT tubes, or other TB culture systems (AFB positive)   1. Broken in transit