Bias And 'Overcall' In Interpreting Chest Radiographs In Young Febrile Children.

Bias and 'overcall' in interpreting chest radiographs in young febrile children.

Few studies have examined the diagnostic validity of the examining physician's interpretation of chest radiographsin young febrile children, and none (to our knowledge) the extent to which the "official" (i.e., the radiologist's) reading may be biased by the access to the examining physician’s reading and toother clinical information. The authors studied 287 consecutive chest radiographs obtained in 286 febrile children 3 to 24 months of age without chronic cardiopulmonary disease or known asthma whopresents to a children's hospital emergency department between March 1989 and August 1990. The readings by treating pediatricians, official pediatric radiologists, and a "blind" pediatric radiologist werecompared. Official radiologists had access to the treating pediatricians' readings and clinical information provided on the radiography requisition. The blind radiologist knew only that each child was 3to 24 months of age and febrile, and he was asked to judge the presence or absence of pneumonia. Using the blind radiologist's reading as the "gold standard" for judging validity of treatingphysicians' and official radiologists' readings, sensitivity (.677 Vs. 647), specificity (.828 Vs. 849), positive predictive value (PPV, .537 Vs. 571), and kappa index (k, .462 Vs. 475) were quite similar. Bycontrast, agreement by the treating physicians was considerably higher with the official radiologists' reading as gold standard: sensitivity =.756, specificity =.922, PPV =.795, and k =.688. When thetreating physician's reading was positive, the official radiologists' positivity rate was much higher than the blind radiologist's (74.4% Vs. 51.8%, P.005), sensitivity was high (.884) butspecificity was low (.436), PPV was .663, and k was .326. When the treating physicians' reading was negative, however, the pattern was reversed: positivity = 8.5% Vs. 12.8% (P not significant), sensitivity =...