Final answer:
The number of blood specimens required for testing after disease exposure varies based on the disease and testing protocols. An initial positive ELISA would necessitate a confirmatory western blot, with further steps if results are indeterminate.
Step-by-step explanation:
The number of blood specimens necessary for testing in cases of disease exposure can vary greatly depending on the disease in question, the type of tests being performed, and the protocols of the healthcare facility. For example, a diagnosis may start with an initial screening test such as the ELISA for certain infections, followed by a confirmatory test like the western blot if the ELISA result is positive. In instances where a patient has a false-positive ELISA test, a western blot would be performed to confirm results. If a western blot test returns indeterminate, the hospital may address this by retesting at a later date, conducting additional tests, or reviewing the patient's clinical context for further clues.
For microscopic examination of stool, several specimens over a number of days are usually analyzed to detect an infection. In clinical blood analysis, technologies such as a lab-on-a-chip are creating avenues for testing multiple diseases quickly and cost-effectively. Furthermore, blood type cross matching is essential before a transfusion, excluding emergency situations where type O blood may be used. Lastly, Wright-Giemsa stained blood smears are evaluated to find indications of stealth microbial infections.