Drug Sensitivity Test, in Delhi

A sensitivity test starts with collecting a clinical sample (urine, blood, wound swab). The lab cultures any bacteria and isolates colonies, then exposes them to antibiotics using disk diffusion (Kirby–Bauer) or dilution methods to determine minimum inhibitory concentration (MIC). After incubation (usually 24–48 hours) the lab measures growth inhibition and reports results as susceptible, intermediate, or resistant to guide treatment.

Five methods of antimicrobial susceptibility testing are: 1) Disk diffusion (Kirby–Bauer) — zone size indicates susceptibility; 2) Broth dilution (macro/micro) — determines minimum inhibitory concentration (MIC); 3) Agar dilution — MIC on solid medium; 4) E-test (gradient strip) — directly reads MIC on agar; 5) Automated systems and molecular tests — phenotypic platforms (VITEK, Phoenix) and genotypic assays detecting resistance genes.

The principle of a sensitivity test is to determine whether a microorganism is susceptible to antimicrobial agents by exposing a standardized culture to defined drug concentrations and measuring growth inhibition. Methods (disk diffusion, broth dilution) assess zone sizes or minimal inhibitory concentrations (MIC). Results are interpreted as sensitive, intermediate, or resistant to guide antibiotic selection and predict likely clinical effectiveness.

A drug sensitivity test for TB determines whether Mycobacterium tuberculosis is susceptible or resistant to anti‑TB medications. Performed on sputum or other clinical samples, it uses rapid molecular assays (e.g., rifampicin resistance and line‑probe tests) and culture‑based drug susceptibility testing. Results guide appropriate therapy and detect drug‑resistant strains (MDR/XDR). Molecular tests yield results in hours–days; culture DST may take weeks.

A drug sensitivity test measures how effectively a specific medicine inhibits or kills bacteria, viruses, or cancer cells grown from a patient’s sample. Lab techniques expose the organism or tumor cells to different drugs and concentrations to identify which treatments work and detect resistance. Results guide clinicians to select the most effective, least toxic therapy, improve outcomes, and reduce unnecessary or ineffective medications.

A culture and sensitivity (C&S) test detects and identifies microorganisms (bacteria or fungi) in samples like urine, blood, sputum or wound swabs. The culture phase grows the organism for identification; the sensitivity (antibiogram) phase determines which antibiotics or antifungals effectively inhibit it and reveals resistance patterns. Results guide targeted antimicrobial treatment and infection control.