What this test measures
The KCLM panel tests Mycobacterium tuberculosis grown on culture against four key second-line drugs: Kanamycin (Km) and Capreomycin (Cm) — both injectable aminoglycosides used historically in MDR-TB regimens — and Levofloxacin (Lfx) and Moxifloxacin (Mfx) — fluoroquinolones, the backbone of modern MDR-TB treatment.
Resistance to either an injectable or a fluoroquinolone, in addition to first-line resistance, defines pre-XDR or XDR TB and dramatically changes the regimen. The result is determined phenotypically on a positive MGIT or LJ culture isolate at WHO-defined critical concentrations.
Why it matters
India's NTEP rolled out shorter and longer MDR-TB regimens that depend heavily on fluoroquinolone sensitivity. Confirming susceptibility to Levofloxacin and Moxifloxacin is therefore essential before placing a patient on either regimen — a fluoroquinolone-resistant strain treated with a fluoroquinolone-based regimen will fail and amplify resistance further.
As WHO and NTEP shift away from injectables (kanamycin, capreomycin) towards all-oral regimens with bedaquiline, linezolid and pretomanid, the KCLM panel still matters for legacy regimens, surveillance and treatment failure investigation.
How to prepare
Requires a positive M. tuberculosis culture (MGIT or LJ). If you do not have one, sputum samples will need to be collected first. Inform the lab of all TB drugs taken in the past.
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| Kanamycin (Km) (—)[1] | Sensitive | — | Resistant — avoid Km. Cross-resistance with capreomycin and amikacin is common. Pre-XDR / XDR-TB pathway applies. |
| Capreomycin (Cm) (—)[1] | Sensitive | — | Resistant — Cm cannot be used. Capreomycin resistance often co-occurs with kanamycin / amikacin resistance. |
| Levofloxacin (Lfx) (—)[1] | Sensitive | — | Resistant — strain is fluoroquinolone-resistant. Moxifloxacin may still work at higher dose if Lfx resistance is low level. Pre-XDR or XDR pathway is triggered. |
| Moxifloxacin (Mfx) (—) | Sensitive | — | Resistant — moxifloxacin should not be used at standard dose; higher-dose moxifloxacin may still be effective in some cases under specialist guidance. |
Pre-XDR and XDR-TB definitions
| Category | Resistance pattern |
|---|---|
| MDR-TB | Isoniazid + Rifampicin |
| Pre-XDR (FQ) | MDR + any fluoroquinolone resistance |
| Pre-XDR (injectable) | MDR + Km or Cm or amikacin resistance |
| XDR-TB (2021 def.) | MDR + FQ resistance + at least one of Linezolid or Bedaquiline resistance |
Frequently asked questions
Why this combination of four drugs?
Kanamycin and capreomycin are the legacy injectables; levofloxacin and moxifloxacin are the modern fluoroquinolone backbone of MDR-TB regimens. Together they cover the most important second-line drug classes.
How long does the test take?
Once a positive culture is in hand, KCLM DST typically takes 1–2 weeks. Total time from sputum to result is often 4–6 weeks.
What if moxifloxacin is resistant but levofloxacin sensitive?
Both are fluoroquinolones and cross-resistance is common, but the pattern depends on the gyrA / gyrB mutation. Your specialist will interpret this in context.
Are injectables still used?
Less so. WHO and NTEP now favour all-oral regimens for most MDR-TB patients using bedaquiline, linezolid and pretomanid. Injectables are reserved for specific scenarios.
How do I take this test under NTEP?
NTEP routes patients with suspected drug-resistant TB through DOTS centres to intermediate / national reference labs. Zelnoo also facilitates private testing through NABL-accredited mycobacteriology labs.
Will the result be definitive?
For the drugs tested, yes. For drugs not included in the panel (e.g. bedaquiline, linezolid, pyrazinamide), separate testing is needed.
Are these tests safe to do at home for sample collection?
Sputum can be collected safely at home with proper instructions; biohazard protocols govern transport. Zelnoo follows NTEP-aligned cold-chain handling.
Related Tuberculosis / Mycobacterial tests
Tests commonly ordered alongside AFB DRUG SUSCEPTIBILITY (KCLM) 2ND LINE, or that help interpret an unexpected result.
Sources & references
- WHO Consolidated Guidelines on Drug-Resistant TB · accessed 2026-05-30T00:00:00.000Z
- NTEP PMDT Guidelines · accessed 2026-05-30T00:00:00.000Z
- India TB Report 2024 · accessed 2026-05-30T00:00:00.000Z
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