AFB LJ Susc - Cycloserine

The AFB LJ Susceptibility – Cycloserine 40 mg/mL test is a specialized drug susceptibility test performed on Mycobacterium tuberculosis isolates grown on Lowenstein-Jensen (LJ) medium. It evaluates whether the tuberculosis-causing bacteria are susceptible or resistant to Cycloserine, a second-line anti-tubercular medication commonly used in the treatment of drug-resistant tuberculosis (DR-TB). The test provides important information that helps clinicians select effective medications and develop an appropriate treatment plan based on the bacterium’s drug susceptibility pattern.

Who should get this test done?

This test may be recommended for individuals who:

●     Have a confirmed Mycobacterium tuberculosis infection requiring drug susceptibility testing.

●     Are suspected of having drug-resistant tuberculosis.

●     Have not responded adequately to first-line anti-tubercular treatment.

●     Require evaluation before initiating or modifying second-line TB therapy.

●     Are undergoing comprehensive drug resistance testing as advised by a tuberculosis specialist.

Why consider this test?

Drug-resistant tuberculosis requires careful selection of medications to ensure successful treatment. The AFB LJ Susceptibility – Cycloserine 40 mg/mL test determines whether the tuberculosis bacteria are likely to respond to Cycloserine, an important second-line anti-TB drug. This information helps healthcare providers avoid ineffective medications, tailor treatment to the patient’s infection, and support better management of drug-resistant tuberculosis.

More information

This test is performed after Mycobacterium tuberculosis has been isolated in culture. The organism is grown on Lowenstein-Jensen (LJ) medium containing a standardized concentration of Cycloserine (40 mg/mL) to evaluate its susceptibility to the drug. It is usually performed as part of a broader panel of anti-tubercular drug susceptibility tests and contributes to a comprehensive assessment of resistance patterns. The results are interpreted along with culture findings, molecular tests, and the patient’s clinical history.

Other names

●     Cycloserine DST, LJ method
●     D-cycloserine susceptibility test
●     MDR-TB cycloserine resistance test
●     AFB drug susceptibility, cycloserine
●     LJ-based cycloserine sensitivity test