AFB Sputum & Bronch Sampling — TB Testing Guidance
Overview
Guidance from Dr. Anglim and the SPH Lab for AFB order processing. The ordering workflow depends on whether tuberculosis is suspected:
- Suspected TB → expedited pathway via Montana State Lab
- TB NOT suspected → standard pathway via ARUP
If Tuberculosis IS Suspected
Order a miscellaneous lab test for Mycobacterium tuberculosis Nucleic Acid Amplification Testing (NAAT) with Rifampin resistance marker for sputum. In the order comments, specify:
“Send to Montana State Lab for suspected tuberculosis active infection.”
What this triggers
| Action | Detail |
|---|---|
| ⚡ Expedited processing | Sputum samples processed faster through State Lab |
| 🏥 Negative pressure room | Patient placed into isolation immediately |
| 🧪 Automatic culture | Mycobacterium spp. Culture Isolation/Identification added automatically |
| 📋 Public health | Gets tracking and support implemented more quickly |
Order Location in EPIC
Miscellaneous Lab → Mycobacterium tuberculosis NAAT with Rifampin resistance marker
If Tuberculosis is NOT Suspected
Looking for MAC (Mycobacterium avium complex), other non-tuberculosis mycobacteria (NTM), or ruling things out?
Order AFB sputum samples through the normal AFB order available in EPIC. In the order comments section, state:
“Tuberculosis is NOT suspected.”
What this means
| Action | Detail |
|---|---|
| 🧪 Processed by ARUP | Will take longer than the State Lab |
| 🏥 No isolation needed | Patient does not require negative pressure or N-95 masks |
| 👥 Typical populations | Cystic fibrosis, immunocompromised patients, NTM workup |
Order Location in EPIC
Normal AFB Order → Available in EPIC order sets
Clinical Scenarios Summary
| Scenario | Order | Comments | Lab | Isolation |
|---|---|---|---|---|
| Suspected TB | NAAT + Rifampin resistance marker | ”Send to Montana State Lab for suspected TB active infection” | Montana State Lab | ✅ Negative pressure |
| MAC / NTM workup | Standard AFB sputum | ”Tuberculosis is NOT suspected” | ARUP | ❌ Not required |
| Immunocompromised / CF | Standard AFB sputum | ”Tuberculosis is NOT suspected” | ARUP | ❌ Not required |
Key Points
- NAAT order = expedited path + automatic isolation + automatic culture add-on
- State Lab is faster for TB workup than ARUP
- Always include the comment specifying TB suspicion status
- The NAAT includes a Rifampin resistance marker — important for MDR-TB screening
References
- SPH Lab / Dr. Anglim — Approved guidance, September 2026
- Montana State Laboratory — TB testing protocols