The example of alleged changes in meaning and significance of
physical signs during the management of cases of suspected appendicitis
given with regard to phase 111 diagnostic studies illustrates how far the
approaches of clinicians and theoreticians diverge. The sign of right
lower quadrant tenderness is NOT "useless in tertiary care." Assuming you
don't "lose" any positives (true and false) on transfer from primary to
tertiary care, the positive predictive value ( TP/ (TP+FP)) is unchanged.
The specificity ratio is irrelevant to this pivotal idea. Equally, not
referring on as many patients without tenderness as those with does not by
any means necessarily affect the accuracy of the sign (True results/
(True + False results)) as stated. This depends in a complex way on
whether you manage the true negatives exactly like the false negatives.
No, GP's and surgeons are right in assigning the same significance to RIF
tenderness, as commonsense indicates.
Rapid Response:
Clinical epidemiology is an oxymoron
The example of alleged changes in meaning and significance of
physical signs during the management of cases of suspected appendicitis
given with regard to phase 111 diagnostic studies illustrates how far the
approaches of clinicians and theoreticians diverge. The sign of right
lower quadrant tenderness is NOT "useless in tertiary care." Assuming you
don't "lose" any positives (true and false) on transfer from primary to
tertiary care, the positive predictive value ( TP/ (TP+FP)) is unchanged.
The specificity ratio is irrelevant to this pivotal idea. Equally, not
referring on as many patients without tenderness as those with does not by
any means necessarily affect the accuracy of the sign (True results/
(True + False results)) as stated. This depends in a complex way on
whether you manage the true negatives exactly like the false negatives.
No, GP's and surgeons are right in assigning the same significance to RIF
tenderness, as commonsense indicates.
GH Hall MD
Exeter EX1 2HW
Competing interests: No competing interests