In screening, two tests are often necessary each with different performance characteristics. These may be offered at the same time (parallel testing) or sequentially (serial testing) .
Parallel versus serial testing.
Two screening tests performed at the same time and the results are subsequently combined
Second screening test is performed only if the result of the first screening test is positive
Higher sensitivity but lower specificity
Improves specificity at the cost of lower sensitivity
1. Sheringham J, Kalim K, Crayford T. Mastering Public Health: A guide to examinations and revalidation. ISBN-13 978-1-85315-781-3.