The CDC standard IIF diagnostic cutoff titer for infection by Leishmania spp. belonging to the donovani complex in dogs is >128 (10 ).
The diagnosis could also be supported by culture of samples obtained by percutaneous lung or pleural fluid aspiration, and/or single diagnostic antibody titer, (IgM), or a four-fold increase in paired serum samples (IgG) for the presumed pathogen.
In this study, at the diagnostic Egyptian MHP titer of 1/160, H agglutinins were less sensitive (by all brands except Dialab) and less specific (by all brands) than O agglutinins and that a raised O agglutinins was of slightly greater diagnostic value than a raised H agglutinins.
Frequently, diagnostic IFA end-point titers were lacking at the time of the patient's first visit.
Such a situation can arise in individuals with low antibody titers to diagnostic antigens like rK39, and immune suppression co- morbidities such as HIV [ 14, 29].
The IFA IgM titer ≥ 1 400 diagnostic criterion showed lower sensitivity and positivity for the MT IBT than the supposedly more stringent four-fold increasing antibody titer in paired samples.
In the endemic region of Australia, the diagnostic sensitivity of an IHA titer of ≥ 1 40 was 56% at the time of admission (using culture as the gold standard), with evidence of subsequent seroconversion on serial IHA testing in 68% of patients who were initially IHA negative.
Commercially available rapid tests, viral culture, immunofluorescence antibody staining, RT-PCR, immunohistochemical staining, and serologic analysis of paired acute-phase and convalescent-phase sera indicating a 4-fold increase in influenza antibody titer were the diagnostic techniques accepted by the EIP.
Because of the difficulty of diagnosing Q fever endocarditis with the current Duke's criteria, particularly when blood cultures are negative and vegetation is absent, a modification has been suggested so that a single positive blood culture or a high anti-phase I antibody titer is considered diagnostic (22 ).
