A Meta-analysis of the diagnostic accuracy of Streptocuccus pneumoniae urinary antigen test for adult ;community acquired Streptocuccus pneumoniae pneumoniae / 中华危重病急救医学

Objective To evaluate the diagnostic accuracy of Streptocuccus pneumoniae urinary antigen test (SpUAT) in patients with community acquired Streptocuccus pneumoniae pneumoniae (SPP). Methods The clinical studies relating SpUAT diagnostic accuracy for community acquired Streptocuccus pneumoniae infection were searched via computer and manual screening of Chinese databases including China National Knowledge Internet (CNKI), China Biology Medicine disc, China Technical Journal Full-text Database, and Wanfang Database as well as English databases such as PubMed, EBSCO, Elsevier Science, Ovid Technologies, and Springer. Data were extracted according to appropriate inclusion and exclusion criteria and analyzed with Meta-disc 1.4 and Stata 12.0 software. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio as well as diagnostic odds ratio (DOR) were calculated, and summary receiver operating characteristic curve (SROC) was plotted and area under SROC (AUC) was calculated to analyze the diagnostic accuracy of SpUAT for adult community acquired SPP. Results A total of 15 studies enrolling 6 866 patients were included, all of which with a quality assessment of diagnostic accuracy studies (QUADAS) score not lower than 10, indicating a high study quality. Random effect model was applied owing to non-threshold effect associated heterogeneity. It was shown by Meta analysis that compared with routine pathogen diagnosis (hemoculture, sputum smears, sputum culture and trachea and bronchus attractive culture), the pooled sensitivity, pooled specificity, pooled positive likelihood ratio, and pooled negative likelihood ratio was 73% [95% confidence interval (95%CI) = 71%-76%,] 91% (95%CI = 90%-92%), 6.97 (95%CI = 4.13-11.77), and 0.30 (95%CI = 0.26-0.34), respectively, pooled DOR was 24.34 (95%CI = 13.14-45.11), and AUC of SROC was 0.8051±0.0362. It was indicated by heterogeneity test that experiment design (prospective or retrospective), sample sizes (lower than 200 or higher than or equal to 200), reference test (fewer than 3 or more than or equal to 3 test methods), or literature language (Hispanic or non-Hispanic) had no effect on study heterogeneity, indicating certain other unknown factors may be involved. Funnel plot suggested that 15 involved studies uniformly distributed along the two sides of regression line, indicating no publication bias. Conclusions The use of SpUAT for the diagnosis of adult community acquired SPP has a moderate sensitivity and high specificity. Although the overall accuracy of SpUAT diagnosis is relatively high, there is significant heterogeneity among the studies, so more high-quality studies are needed.

Investigation of Positive Streptococcus pneumoniae Urinary Antigen Test Results in a Korean University Hospital / 대한임상미생물학회지

BACKGROUND: The Streptococcus pneumoniae urinary antigen test (SPUAT) (Binax Now, USA) was developed for detecting polysaccharide C in urine samples for rapid diagnosis of pneumococcal pneumonia, the most common cause of community-acquired pneumonia (CAP). To validate positive results of these tests, we retrospectively investigated all positive results obtained from the emergency room of a Korean university hospital among patients with suspected CAP. METHODS: One hundred twenty-three positive SPUAT results were abstracted and analyzed from the authors' laboratory information system among the SPUAT results performed from 1,143 pneumonic patients admitted from the emergency room of a university hospital between 2007 and 2008. Medical records, including conventional microbiologic analysis results, were reviewed in detail for all positive test results. RESULTS: Among 123 patients with the positive SPUAT results, 24 patients were excluded due to hospitalization history during the preceding month. Nine of 99 patients (9.1%) with suspected CAP had confirmed pneumococcal pneumonia upon conventional sputum or blood culture. Thirty-five positive results (35.4%) showed other microorganisms upon conventional methods, which might be due to possible cross-reactivity. Among those, 23 positive results were considered bacterial pneumonic agents, and 12 positive results were regarded as urinary tract infection strains or contaminating agents. Fifty-five positive SPUAT results (55.6%) showed negative conventional microbiologic growth, and some positive SPUAT results might be caused by true pneumococcal infection although without cultural evidence. CONCLUSION: Our retrospective study demonstrated that a positive SPUAT result typically does not agree well with conventional culture methods, suggesting that the value of a positive SPUAT result in etiology determination may be limited under practical conditions in a university hospital.

Clinical Relevance of Positive NOW(TM) Legionella Urinary Antigen Test in a Tertiary-Care Hospital in Korea / 대한진단검사의학회지

BACKGROUND: The morbidity and mortality of Legionnaires' disease are not established in Korea, because patients with community-acquired pneumonia (CAP) have rarely been investigated for Legionella. An assay for Legionella antigen in urine has been approved as one of the diagnostic criteria of Legionnaires' disease. Binax Now(TM) Legionella Urinary Antigen Test (LUA) was introduced in Asan Medical Center in July 2002. The purpose of this study was to evaluate the clinical relevance of positive LUA. METHODS: During the 39-month period from July 2002 to September 2005, the medical records of LUA-positive patients were reviewed for demographic findings, laboratory findings, clinical diagnosis, antimicrobial treatment, outcome, and acquisition of infections. Diagnosis of Legionnaires' disease was based on National Nosocomial Infections Surveillance (NNIS) criteria for defining nosocomial pneumonia. RESULTS: Seven (0.3%) of the 2443 patients tested for LUA were positive. All 7 patients were consistent with the diagnostic criteria of Legionnaires' disease; six patients were diagnosed with CAP and one patient was admitted due to nosocomial pneumonia. Six patients were treated with azithromycin or ciprofloxacin but one patient was not treated for Legionella infection. With the report of LUApositive results, a Legionella-targeted treatment was started in two patients and an inappropriate empirical therapy was ceased in one patient. All patients treated with Legionella-targeted treatment improved clinically except one who died of adult respiratory distress syndrome at the first hospital day. CONCLUSIONS: Positive LUA is useful in diagnosing Legionnaire's disease at an early stage and in helping to initiate appropriate treatments in a tertiary-care hospital in Korea.

Evaluation of Urinary Antigen Test for Rapid Diagnosis of Community-Acquired Pneumococcal Pneumonia / 대한임상미생물학회지

BACKGROUND: Streptococcus pneumoniae is one of the most common pathogens of communityacquired pneumonia (CAP) which needs rapid diagnosis and appropriate therapeutic approaches. We evaluated a new rapid urinary antigen test kit, NOW S. pneumoniae antigen test (Binax Inc., Maine, USA), for the detection of the S. pneumoniae antigen in the urine of patients who were suspected of CAP. METHODS: A total of 115 urine samples were tested during April to July, 2004. Patients were divided into 2 groups: the first was the patients who were suspected of CAP and the second was the patients with other disorders. Urinary antigen test was performed done by immunochromatographic methods and results were read within 15 minutes. All the urine samples were random and unconcentrated. The patients were reviewed clinically, together with the results of sputum and blood cultures, urinalysis and other laboratory tests. RESULTS: Overall mean age was 62-years old and male proportion was 59%: Group 1 had mean age of 63-years old and male 54% whereas group 2 had 60-years old and 76%. S. pneumoniae antigen was detected in the urine from 14 (12.2%) of 115 patients. Of the 14 patients with positive urinary antigen tests, 12 were from 90 patients with CAP with fever, leukocytosis and appropriate radiological findings, giving the sensitivity of 13.3%; the remaining 2 patients were from 25 patients with other disorders. Only 2 of the 12 patients showed S. pneumoniae in sputum or blood cultures, respectively. Urinary antigen was not detected in 23 of the 25 patients with other disorders, giving the specificity of 92%. CONCLUSIONS: Since this simple and rapid urinary antigen test showed low sensitivity in this study, the clinical symptoms and signs and radiological findings of patients should be reviewed together with the results of the urine test for early and accurate diagnosis and treatment, consistent clinical symptoms and signs with radiological studies are inevitable. Thus further studies would be necessary. The urinary antigen test showed high specificity and therefore should be a useful adjunct to cultures to be in aid of the diagnosis of CAP.