Using a combination of reference tests to assess the accuracy of a new diagnostic test. Stat. Med

Often the accuracy of a new diagnostic test must be assessed when a perfect gold standard does not exist. Use of an imperfect reference test biases accuracy estimates of the new test. This paper reviews existing approaches to this problem including discrepant resolution and latent class analysis. Deciencies with these approaches are identied. A new approach is proposed that combines the results of several imperfect reference tests to dene a better reference standard. We call this the composite reference standard (CRS). Using the CRS, accuracy can be assessed using multi-stage sampling designs. Maximum likelihood estimates of accuracy and expressions for the variance of sensitivity and specicity are provided. Data from clinical literature on the detection of Chlamydia trachomatis are used to illustrate and compare the dierent approaches. Advantages of the CRS relative to other approaches include that the CRS is explicitly dened, does not depend on the results of the new test under investigation, and is easy to interpret. Copyright? 1999 John Wiley & Sons, Ltd. 1