Sensitivity, specificity, positive and negative predictive values: diagnosing purple mange.
OBJECTIVE
To shed light on several epidemiological terms for better understanding of diagnostic testing measures by using a mythical condition, "purple mange."


METHODS
Scientific literature related to epidemiology and statistical tests.


CONCLUSIONS
Nurse practitioners (NPs) use the concepts of sensitivity (SEN), specificity (SPEC), positive predictive value (PPV), and negative predictive value (NPV) daily in primary care and specialty areas. In addition, PPV and NPV vary with the prevalence of a condition. At times, NPs misunderstand the meaning of these terms.


CONCLUSIONS
In order to develop appropriate treatment plans, an understanding of the concepts of SEN, SPEC, PPV, and NPV is important for interpreting test results. The authors have used this mythical condition purple mange as a teaching tool for NP students.
Collier
Jill
J
University of Wisconsin Oshkosh College of Nursing, Graduate Program, Oshkosh, Wisconsin, USA. collierj@uwosh.edu
Huebscher
Roxana
R
D003141:Communicable Diseases / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology; D003362:Cost-Benefit Analysis; D003937:Diagnosis, Differential; D019937:Diagnostic Techniques and Procedures / Q000191:economics / Q000592:standards*; D004812:Epidemiologic Methods; D006801:Humans; D008403:Mass Screening / Q000191:economics / Q000379:methods / Q000592:standards; D009722:Nurse Practitioners; D011237:Predictive Value of Tests; D015995:Prevalence; D011320:Primary Health Care / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity