Explain series interpretation of lab tests

• A. with series interpretation only animals that test positive to both tests are considered test positive
• B. with series interpretation, any positive test makes it positive
• C. series interpretation uses parallel testing logic
• D. series interpretation ignores test results

Answer: (A)

In series interpretation, you call an animal positive only if it tests positive on both tests. This is serial testing: you require concordant positive results from multiple tests before declaring infection. The reason this is the best description is that requiring all tests to be positive markedly increases specificity, because the chance of a false positive on both tests is lower than on either test alone. However, this comes at the cost of sensitivity: if either test misses an infection (a false negative), the combined result will be negative even though the animal is infected.

So, this approach aligns with the idea of using multiple tests in sequence to confirm status, rather than a single positive result sufficing. The alternative notions—calling someone positive if any test is positive (parallel testing) or ignoring test results—do not describe the series approach.