ICD-10 Code for Positive QuantiFERON Test
The appropriate ICD-10 code for a positive QuantiFERON (IGRA) test indicating latent tuberculosis infection is R76.12 (Nonspecific reaction to tuberculin skin test without active tuberculosis) or Z11.1 (Encounter for screening for respiratory tuberculosis), but the most clinically accurate code is Z22.7 (Latent tuberculosis) when LTBI is confirmed.
Understanding the Clinical Context
A positive QuantiFERON test indicates M. tuberculosis infection but requires exclusion of active disease before coding as LTBI 1. The CDC guidelines emphasize that tuberculin testing (including IGRAs like QuantiFERON) is performed to identify persons at increased risk for progression to active TB or those with latent infection 1.
Coding Algorithm Based on Clinical Scenario
When Active TB is Ruled Out:
- Use Z22.7 (Latent tuberculosis) - This is the definitive code when chest X-ray and clinical evaluation exclude active disease and the patient has a confirmed positive IGRA 1
- This code applies when the patient meets criteria for LTBI: positive test result AND negative evaluation for active tuberculosis 2
During Initial Screening Phase:
- Use Z11.1 (Encounter for screening for respiratory tuberculosis) - Appropriate when the test is performed as part of screening before confirming LTBI status 1
- This applies to high-risk populations including recent immigrants, healthcare workers, prison residents/employees, and injection drug users 1
For Positive Test Result Alone:
- Use R76.12 (Nonspecific reaction to tuberculin skin test without active tuberculosis) - Can be used for a positive IGRA result when further evaluation is pending 1
- Note: While this code references "tuberculin skin test," it is commonly applied to positive IGRA results in practice
Risk-Stratified Interpretation Matters for Documentation
The CDC guidelines stratify QFT interpretation by risk level, which should inform your clinical documentation 1:
- Increased risk populations (recent immigrants from high-prevalence countries, injection drug users, prison populations, healthcare workers): percentage tuberculin response >15 is considered positive 1
- Low risk populations (military personnel, low-risk healthcare workers, U.S.-born students): percentage tuberculin response >30 is considered positive 1
Critical Documentation Requirements
Before finalizing the LTBI code (Z22.7), ensure documentation includes 1, 3:
- Positive QuantiFERON result with specific values meeting CDC criteria 1
- Chest radiography results excluding active TB 3
- Clinical evaluation ruling out symptoms of active disease (cough, fever, weight loss, night sweats) 3
- Risk factor assessment (BCG vaccination status, immunosuppression, TB exposure history) 1, 4
Common Coding Pitfalls to Avoid
- Do not use active TB codes (A15.x series) when only IGRA is positive without evidence of active disease 1, 3
- Do not code as "negative" or "normal" simply because the patient is asymptomatic - LTBI is asymptomatic by definition 2
- Do not use R76.11 (Nonspecific reaction to tuberculin skin test without active tuberculosis, abnormal result) interchangeably - R76.12 is more specific for confirmed positive results 1
- Avoid coding before active TB is excluded - premature use of Z22.7 without chest X-ray and clinical evaluation is inappropriate 3
Special Considerations for Immunocompromised Patients
In HIV-infected or immunosuppressed patients, IGRAs may have reduced sensitivity 4. Document:
- CD4 count if HIV-positive (affects test interpretation) 4
- Other immunosuppressive conditions or medications 3
- Consider dual testing approach (TST plus IGRA) in this population for optimal sensitivity 4
When Treatment is Initiated
Once LTBI treatment begins, you may add 3:
- Z79.2 (Long-term use of antibiotics) - if using rifampin or isoniazid regimens
- Continue using Z22.7 as the primary diagnosis throughout treatment course 3