We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Article |

Problematic Prostatic Prediction

Michael Davidson, MD, MPH; Loic LeMarchand, MD
JAMA. 1985;254(9):1173. doi:10.1001/jama.1985.03360090061012.
Text Size: A A A
Published online


To the Editor.—  Chodak and Schoenberg1 address the important issue of efficacy of prostate cancer screening by digital rectal examination but have mislabeled an important parameter of that test. The authors repeatedly refer to a test "specificity of 29%" erroneously calculated as (true test positives/true test positives+false test positives) and compared it with that reported by others. The value they calculated was really the positive predictive value. The specificity of a test should represent the percentage of negative tests among patients free of disease (true test negatives/true test negatives+false test positives).Unless an appropriate gold standard is available to distinguish those individuals who are truly test negative from those with early undetectable disease (false test negatives), the specificity of a screening test must assume a low disease prevalence with a few false-negatives "contaminating" both the numerator and denominator. The high prevalence in older men of microscopic prostate cancers (almost


Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?




Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.