RT Journal Article
SR Electronic
T1 Diagnosis of conjunctivitis in primary care: comparison of two different culture procedures
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 939
OP 941
DO 10.1136/jcp.2009.064444
VO 62
IS 10
A1 E Tellegen
A1 G ter Riet
A1 J H Sloos
A1 H C P M van Weert
YR 2009
UL http://jcp.bmj.com/content/62/10/939.abstract
AB Background: In general practice, infectious conjunctivitis is a common and mostly (64%) self-limiting disorder. In case of an aberrant course or severe symptoms, a general practitioner may take a culture. Direct inoculation is considered the reference standard, but usually a swab is sent to a laboratory.Objectives: To compare the diagnostic performance of the swab, transported by surface mail with direct inoculation.Methods: 19 general practitioners took two samples of the conjunctiva from 88 patients with symptoms suggestive of infectious conjunctivitis by rolling a cotton swab across the conjunctiva of the lower fornix. One swab was used to inoculate three agar plates directly, while the other was sent in a Stuart medium to the laboratory and inoculated at the time of arrival. The numbers of positive cultures of both methods were compared.Results: A pathogen was found in 31 of 88 samples (35% (95% CI 26 to 46)). Surprisingly, the number of positive cultures was higher for the Stuart medium (27/88) than for direct inoculation (23/88). The difference was 4.5% (90% CI 0 to 12, p = 0.388; one-sided McNemar test for paired proportions). In five of the 19 samples that were positive in both tests, the cultured pathogens were different.Conclusions: The Stuart medium detected more bacteria than direct inoculation. The lower 90% CI, testing non-inferiority at p = 0.05, indicates that it is unlikely that the Stuart medium misses any positive cultures compared with direct inoculation.