If paratyphoid fever is suspected, the most accurate method to confirm the diagnosis is through laboratory testing that detects the presence of Salmonella Paratyphi bacteria in the body. The blood culture is considered the most reliable test, especially during the first week of illness, when the bacteria are actively circulating in the bloodstream. A small sample of blood is cultured in the laboratory to identify the specific strain of Salmonella, and results can take a few days. As the illness progresses, the bacteria may become less detectable in the blood but more likely to appear in stool or urine cultures, which are often used in the second week or later to confirm or monitor infection. Stool cultures are also useful for identifying carriers—people who no longer have symptoms but continue to shed the bacteria. The Widal test, a serological test that measures antibodies, is sometimes used in resource-limited settings, but it is less specific and can give false results, so it’s not as reliable as a culture. In summary, a blood culture done early in the illness provides the most accurate confirmation, while stool or urine cultures are better for later stages or follow-up testing.