What this test measures
The KEPO panel tests Mycobacterium tuberculosis on culture against four second-line drugs that formed the backbone of older MDR-TB regimens: Kanamycin (Km, injectable aminoglycoside), Ethionamide (Eto, thioamide), Para-aminosalicylic acid (PAS, oral bacteriostatic), and Ofloxacin (Ofx, older fluoroquinolone).
Results are reported as sensitive or resistant at WHO-defined critical concentrations. While newer regimens have largely replaced ofloxacin with levofloxacin / moxifloxacin and reduced reliance on injectables and PAS, the KEPO panel is still used in many Indian labs to evaluate isolates against legacy regimens, for surveillance, and to interpret historical resistance.
Why it matters
India's MDR-TB programme transitioned over the past decade from kanamycin-based and ofloxacin-based regimens to newer all-oral combinations with bedaquiline, linezolid, and moxifloxacin. The KEPO panel remains useful in:
- Patients previously treated with the older regimen, when evaluating retreatment options. - Resource-constrained settings where newer drugs are not available. - Programmatic surveillance of second-line drug resistance trends. - Confirming ofloxacin resistance, which usually predicts (but does not always equal) moxifloxacin resistance.
Pair KEPO with a moxifloxacin- and linezolid-containing panel for a complete picture in modern MDR / pre-XDR / XDR-TB workups.
How to prepare
A positive M. tuberculosis culture is required. If not yet available, sputum sample(s) will need to be collected for AFB MGIT culture first. Inform the lab of all TB drugs taken previously.
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 — Km cannot be used. Cross-resistance with capreomycin / amikacin is common, raising the pre-XDR / XDR question. |
| Ethionamide (Eto) (—)[1] | Sensitive | — | Resistant — Eto should not be used. Cross-resistance with isoniazid (via inhA mutations) is well-documented; check inhA status if known. |
| PAS (—)[1] | Sensitive | — | Resistant — PAS cannot be used. PAS is generally reserved for salvage regimens and has significant GI tolerability issues. |
| Ofloxacin (Ofx) (—) | Sensitive | — | Resistant — usually predicts levofloxacin and moxifloxacin resistance, though some moxifloxacin-only susceptibility is possible at high dose. Triggers pre-XDR pathway. |
Second-line TB drug classes
| Class | Drugs | Use today |
|---|---|---|
| Fluoroquinolones | Levofloxacin, Moxifloxacin (Ofloxacin — older) | Core MDR regimen backbone |
| Injectables | Kanamycin, Capreomycin, Amikacin | Largely replaced by all-oral regimens |
| Thioamides | Ethionamide, Prothionamide | Companion drug, GI tolerability limits use |
| PAS | PAS | Salvage regimen only |
| Newer agents | Bedaquiline, Delamanid, Linezolid, Pretomanid | Modern MDR / XDR backbone |
Frequently asked questions
Why include ofloxacin if it is rarely used now?
Ofloxacin resistance usually predicts resistance to the newer fluoroquinolones (levofloxacin, moxifloxacin) used today. It is also a marker of the gyrA / gyrB mutation status.
What if PAS is sensitive but I have never taken it?
PAS sensitivity is reassuring — it means the drug remains a potential option for salvage regimens. PAS is rarely needed in modern regimens but is held in reserve.
Should I do KEPO or KCLM?
They cover overlapping but different drug sets. KCLM covers the modern fluoroquinolones (levofloxacin, moxifloxacin) and injectables; KEPO covers older fluoroquinolone (ofloxacin), an injectable (kanamycin), ethionamide and PAS. Many specialists request both for a complete MDR-TB picture.
How long does the result take?
About 1–2 weeks from a positive culture, so 4–6 weeks total from sputum collection to result.
Is this test available under NTEP?
Yes — NTEP intermediate and national reference labs offer second-line DST free of charge to programme-enrolled patients. Private testing is also available.
How are ethionamide-resistant strains treated?
Ethionamide is dropped from the regimen and replaced by another companion drug guided by the full DST profile and specialist input.
Are newer drugs in this panel?
No — bedaquiline, linezolid, delamanid and pretomanid are tested through separate panels and molecular tests like Xpert MTB/XDR.
Related Tuberculosis / Mycobacterial tests
Tests commonly ordered alongside AFB DRUG SUSCEPTIBILITY (KEPO) 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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