Three commonly used tests for carpal tunnel syndrome are tinel’s sign, phalen’s test, and the nerve conduction velocity test. tinel’s sign and phalen’s test are both highly sensitive (0.97 and 0.92, respectively) and specific (0.91 and 0.88, respectively). the sensitivity and specificity of the nerve conduction velocity test are 0.93 and 0.87, respectively.
assume that the tests are conditionally independent.
calculate the sensitivity and specificity of a combined test if combining is done:
(a) in a serial manner;
(b) in a parallel manner.
(c) find positive predictive value (ppv) for tests in (a) and (b) if the prevalence of carpal tunnel syndrome in the general population is approximately 50 cases per 1000 subjects.
tests are combined in a serial manner if the combination is declared positive when all tests are positive.
tests are combined in a parallel manner if the combination is declared positive when at least one test is positive.