The Weil–Felix Test is an Agglutination Test for the Diagnosis of Rickettsial Infections.

It was First Described in 1916.

By Virtue of its Long History and of its Simplicity,

It has Been one of the Most widely employed tests for rickettsia on a global scale, despite being superseded in many settings by more sensitive and specific diagnostic tests.

Procedure :

The Weil–Felix Test Can be Done as Either a Slide or a Tube Test.

The Antigens Necessary (OX2, OX19, and OXK) can be Obtained Commercially.


Proteus OXK Strain Agglutinins are Produced in Scrub Typhus And OX 2 and OX 19 Agglutinins in other Rickettsial Diseases, as follow :

Organism Weil-Felix Reaction
OX 19 OX 2 OXK
R. prowazekii + + + +/- –
R. typhi + + + +/- –
R. tsutsugamushi – – + + +
R. rickettsii +/ + + + +/ + + + –