In VDRL test,to detect the reagin Ab,the cardiolipin Ag is used.Cardiolipin is extracted from beaf heart & the ‘C’ particle is coated to cadiolipin.These Ag is then mixed with the pt’s serum.The test is reactive when the agglutination occurs.Such reactive test is done by serial dilution of serum to detect the titre of reagin Ab.
This test is reactive in some other diseases in low dilution at or below one in two dilution.The disease are:
- Collagen disease.
- Kala azar.
- Mumps etc.
- Outcome of treatment can only by assessed by VDRL test.
- Test can be used as screening test.
- Test is comperatively cheaper than TPHA.
Disadvantage: False positive i.e test may become positive in other dise