This Article  • References  • Full text PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Contact me when this article is cited  Related Content  • Similar articles in JAMA  Social Bookmarking   What's this?

Eugene L. Gottfried, MD
University of California San Francisco

JAMA. 1986;255(14):1876-1877.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

To the Editor.—

The clinical value of a laboratory test depends on more than just a statistically significant difference between two test groups. Grimm et al¹ may have overemphasized the prognostic importance of the white blood cell count for coronary heart disease. The unwary may be misled into believing that a blood cell count can actually identify persons at risk.

When the test groups are large, even minor differences may be statistically significant. For example, in one study of about 1,300 healthy subjects,² there was a small but highly significant sex difference in the platelet count (P<.0001). Even so, there are better ways than a platelet count to separate the girls from the boys! . . . [Full Text PDF of this Article]

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?