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Previous Volume 330:370-371 February 3, 1994 Number 5 Next

	Since this article has no abstract, we have provided an extract of the first 100 words of the full text and any section headings.

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To the Editor: We wish to point out a potentially confusing result in the work of Zangwill and colleagues (July 1 issue)¹. In the Abstract and Results section they state that the positive predictive value of the indirect fluorescent-antibody test for Rochalimaea henselae was 91 percent. We suggest that it is not possible to determine the predictive value of a test in a case-control study.

The predictive value of a test is strongly influenced by the prevalence of the condition in a population². In a case-control study, the prevalence of a condition is artificially fixed by the number . . . [Full Text of this Article]

References

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