You have diagnosed a patient clinically as having SLE and ordered 6 test. Out of which 4 test have common positive and 2 are negative. To determine the probability of SLE at this point,you need to know:

• A. Incidence and prevalence of SLE
• B. Relative risk of SLE in this patient
• C. Prior probability of SLE;sensitivity and specificity of each test
• D. Incidence of SLE and predictive value of each test