BACKGROUND: Correct interpretation of screening spirometry results is
essential in making accurate clinical diagnoses and directing subseque
nt pulmonary evaluation. The general internist is largely responsible
for interpreting screening spirometric tests at community hospitals. H
owever, reports of new guidelines for screening spirometry are infrequ
ently published in the general internal medicine literature. This can
lead to incorrect interpretations. We sought to evaluate whether spiro
metric interpretations by a group of practicing general internists dif
fered from those of two board-certified pulmonologists using guideline
s published by the American Thoracic Society (ATS). METHODS: As part o
f a Continuous Quality Improvement project, all available screening sp
irometric tests over a 3-month period at two area community hospitals
were reviewed. Only those performed on individuals age 18 or older wer
e included in the analysis. Comparison was made between the interpreta
tions of staff internists and those of two pulmonologists, who were bl
inded to the results of all other interpretations. We analyzed 110 scr
eening spirometric tests from 84 males and 26 females. The patients ra
nged in age from 18 to 77 (mean 41 +/- 13 years of age). RESULTS: Ther
e was 97% concordance between the two pulmonologists' interpretations.
In three cases, interpretations of only one pulmonologist agreed with
those of the internists. The internists and both pulmonologists agree
d in 73 cases. The majority of spirometric results in this subgroup we
re normal (n = 54). Both pulmonologists disagreed with internists' nom
enclature in five cases, There was complete disagreement between the p
ulmonologists and the internists in the other 29 cases. Using the pulm
onologists' interpretations as the ''gold standard,'' the sensitivity
(the internists' ability to correctly identify abnormal spirometric re
sults) was 58.8% (95% confidence interval [CI] 42.2%, 73.3%), the spec
ificity was 81.8% (95% CI 70.0%, 89.8%), the positive predictive value
was 66.7% (95% CI 49.0%, 80.9%), and the negative predictive value wa
s 76.1% (95% CI 64.3%, 85.0%). The most common inaccurate Interpretati
ons made by internists were ''small airways disease'' when spirometric
results were normal (n = 8); ''normal'' when a restrictive pattern wa
s present (n = 6), and ''normal'' when an abnormal flow-volume loop su
ggesting possible upper airway obstruction was present (n = 5) CONCLUS
IONS: The spirometric interpretations of a group of general internists
differed significantly from those of two board-certified pulmonologis
ts using published guidelines in approximately one third of cases. Thi
s may be because subspecialty guidelines are infrequently published in
the general internal medicine literature. We believe that wider disse
mination of these interpretative guidelines and ongoing physician educ
ation would improve general internists' ability to identify patients w
ho require further pulmonary evaluation.