# Lab Tests

 The flashcards below were created by user julieaburch on FreezingBlue Flashcards. Can calculate the revised probability (RP) from the initial probability (IP) of the diagnosis by knowing what 3 things? What is this called? The prior probability of the diseaseThe probability of a positive test result with the diseaseThe probability of a positive test result without the diseaseCalled Bayes' Theorem Good as screening test in disease with low prevalence; low false-negative (FN) rate; e.g. cancer screening tests, PSA, ELISA, HIV, etc. High Sensitivity A test with a low false-positive (FP) rate; good for confirming a positive obtained on a screening test; e.g. a positive ELISA HIV test must then be confirmed with a Western Blot assay High Specificity The percentage of patients with a "positive" result from a population with the disease (TPR) Sensitivity of True Positive Rate (TPR) The percentage of people with a "negative" test in a population without the disease (TNR) Specificity of True Negative Rate (TNR) False positive rate = ? FPR = 1 - specificity False negative rate = ? FNR = 1 - sensitivity SNOUT SeNsitivity "N" test rules out or Sn-N-Out disease:High sensitivity + Negative result --> Rules out diagnosis SPIN SPecificity "P" rules IN or Sp-P-IN disease: High specificity + Positive result --> Rules in diagnosis The ratio of the probability of finding a positive test in the presence of disease to the probability of a positive test in the absense of disease Likelihood Ratio Authorjulieaburch ID47797 Card SetLab Tests DescriptionLab Tests Updated2010-11-07T02:16:23Z Show Answers