Principle: It is an agglutination test which detects the presence of antibodies against salmonella in the blood flow flowing typhoid and parathyphoid fever.
Types:Its is antibodies detected uncle titer in healthy population:
- TO-1:80(Somatic antibody of S.typhi)
- TH-1:80(Flagellar antibody of S.typhi)
- AH-1:40(Flagellar antibody of S.para typhi A)
- BH-1:40(Flagellar antibody of S.para typhi B)
- ‘O’antibody is Ig M.Which increase in recent infection and short lasting and ‘H’antibody is Ig type which is long lasting.
- Antibodies begin to appear in serum after 10 days.
- Single titer is not diagnostic,rising titer is significat(rising titer means ther is increase in titer between two samples at 4-5 days interval)
- Fold rise of normal titer is also significant.
- Local titer various froms region to region.
- Anamenstic reaction due to cross reaction their transient rise of ‘H’antibody titer.
- Titer in vaccinated persons depends on duration.
- Carrier may be positive in health carries.