B. Widal test.
C. Urine culture.
D. Gram’s staining.
Ans:B. Widal test.
Step ladder pyrexia and Rose spots over the body is shown in the image.
The patient in question is probably suffering from Typhoid fever.
Laboratory diagnosis of typhoid
|Diagnostic test||Sensitivity range (%)||Specificity range (%)||Comments|
|Blood culture||40-80||NA||Widely regarded as the gold standard, but sensitivity may be low in endemic areas with high rates of antibiotic use—hence true specificity is difficult to estimate|
|Bone marrow cultures||55-67||30||Greater sensitivity but invasive and thus of limited clinical value, especially in ambulatory management|
|Urine culture||0-58||NA||Variable sensitivity|
|Stool culture||30||NA||Sensitivity lower in developing countries and not used routinely for follow-up|
|Polymerase chain reaction||100||100||Promising, but initial reports indicated similar sensitivity to blood cultures and lower specificity|
|Nested polymerase chain reaction||100||100||Promising and may replace blood culture as the new “gold standard”|
|Widal test (tube dilution and slide agglutination)||47-77||50-92||Classic and inexpensive. Widal test (demonstration of antibodies against Salmonella antigens O-somatic and H-flagellar).The Widal test is time-consuming, and prone to significant false positive results.|
|Typhidot||66-88||75-91||Lower sensitivity than Typhidot-M.Typhidot is a medical test consisting of a dot ELISA kit that detects IgM and IgG antibodies against the outer membrane protein (OMP) of the Salmonella typhi. The typhidot test becomes positive within 2–3 days of infection and separately identifies IgM and IgG antibodies.|
|Typhidot-M||73-95||68-95||Higher sensitivity and specificity than classic Typhidot in some series, but other evaluations suggest that the performance may not be as robust in community settings as in hospital|
|Tubex||65-88||63-89||Promising initial results but has yet to be evaluated in larger trials in community settings|
|Urine antigen detection||65-95||NA||Preliminary data only|