Point-of-care testing in microbiology: the advantages and disadvantages of immunochromatographic test strips

Abstract

Background: Point-of-care testing (POCT) for the demonstration of pathogens was introduced several years ago. The present study describes the current technical status of POCT, giving some examples, and summarizes the specific advantages and disadvantages of the POCT approach in microbiology.

Methods: Selective review of the literature found in medical databases under consideration of current German and international guidelines.

Results/conclusions: The test systems available today are technically mature and offer good to very good performance. For HIV, malaria, group A streptococci, and legionellae, POCT testing, when indicated, is on a par with conventional procedures. The information yielded by rapid tests for pneumococci and for influenza tends to be supplementary in nature. The rapid test for group B streptococci is unsuitable for routine use because its sensitivity is still too low compared with bacterial culture. POCT can be successful only if the tests are performed correctly by trained personnel, quality management procedures are followed, and the severity of illness and the epidemiological circumstances are taken into account when interpreting the results.

Keywords: diagnosis; immune diagnosis; infection risk; laboratory diagnosis; rapid testing.

Figure 1

Sensitivity of the pneumococcal antigen test (Binax NOW) in dependence on the severity of the pneumonia, as measured with the pneumonia severity index (PSI) or the status of the blood culture (BC). The sensitivity of the test was 94% with PSI>90 and 63% with PSI<90 (p<0.001). The sensitivity of the test was 92% with positive blood culture and 74% with negative blood culture (p-value, not significant). The specificity of the test was 100% in the patient group examined (95% confidence interval 99.7% to 100%). Taken from Roson et al., 2004 (14).