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Investing time in microscopy: an opportunity to optimise smear-based case detection of tuberculosis

Cambanis, A., Ramsay, Andrew, Wirkom, V., Tata, E. and Cuevas, Luis ORCID: (2007) 'Investing time in microscopy: an opportunity to optimise smear-based case detection of tuberculosis'. International Journal of Tuberculosis and Lung Disease, Vol 11, Issue 1, pp. 40-45.

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SETTING: St. Elizabeth Hospital, rural North-west Cameroon, an area with high tuberculosis (TB) and human immunodeficiency virus (HIV) incidence.
OBJECTIVE: To measure the time spent during routine sputum smear microscopy and assess whether reexamining slides for 10 min translates into higher case detection of smear-positive cases.
DESIGN: A prospective observational study over a 6-month period with three components: 1) timing of routine sputum smear examination; 2) blinded reexamination of all slides for 10 min and results compared with initial readings; and 3) blinded re-examination, by the original microscopists, of a portion of false-negative slides mixed with true negatives for 10 min.
RESULTS: A total of 204 patients submitted 612 sputum specimens for screening. The median routine examination time was 2 min 6 seconds (interquartile range 1:30-2:30). A 10 min examination significantly increased the number of positive smears from 82 to 116 (P = 0.0083), and overall case detection from 28 to 48 patients (P = 0.011). On review by the original readers, more than half of the false-negative slides were reported as positive after 10 min. CONCLUSION: Sputum smear microscopy has low sensitivity if performed too quickly, and 10 min re-examination significantly increases case detection. Ensuring that smears are examined for the recommended duration may be a simple and low-cost way to improve case detection.

Item Type: Article
Uncontrolled Keywords: tuberculosis case finding diagnosis smear-positive pulmonary sputum smear microscopy pulmonary tuberculosis hiv countries district malawi era
Subjects: QY Clinical Pathology > Diagnostic Tests > QY 120 Sputum
QY Clinical Pathology > Diagnostic Tests > QY 250 Immunodiagnostic tests
QY Clinical Pathology > QY 4 General works
WB Practice of Medicine > Diagnosis > General Diagnosis > WB 200 Physical diagnosis (General)
WF Respiratory System > Tuberculosis > WF 200 Tuberculosis (General)
WF Respiratory System > Tuberculosis > WF 220 Diagnosis. Prognosis
WF Respiratory System > Tuberculosis > WF 300 Pulmonary tuberculosis
Faculty: Department: Groups (2002 - 2012) > Child & Reproductive Health Group
Groups (2002 - 2012) > Clinical Group
Depositing User: Ms Julia Martin
Date Deposited: 22 Sep 2010 15:31
Last Modified: 06 Feb 2018 13:01


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