The test is based on cross‑reaction between Rickettsial antibodies and Proteus OX strains (OX‑2, OX‑19, OX‑K).

Clinical uses include:

Screening for Rickettsial infections such as epidemic typhus, endemic typhus, scrub typhus, and spotted fever.

Supporting diagnosis in resource‑limited settings where advanced tests are unavailable.

Limitations:

Low sensitivity and specificity; false positives and false negatives are common.

Modern diagnostic methods (e.g., ELISA, IFA, PCR) are more reliable, but Weil–Felix is still used in some regi

Analyte: Antibodies against Rickettsia (detected via cross‑reaction with Proteus antigens).

Normal Result: Negative (no agglutination).

Abnormal Findings:

Positive agglutination with OX strains: Suggests Rickettsial infection.

OX‑19: Associated with epidemic typhus and spotted fever.

OX‑2: Associated with certain spotted fevers.

OX‑K: Associated with scrub typhus.

Clinical Use:

Provides a simple, inexpensive screening tool for Rickettsial diseases.

Helps guide diagnosis in endemic areas.

Supports infectious disease and tropical medicine evaluations.