Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are two important viral pathogens that cause respiratory tract infections in the pediatric population. The rapid detection of these agents allows the prompt isolation and treatment of infected patients. In the present prospective study, we evaluated the performances of four rapid antigen detection assays, including a rapid chromatographic immunoassay ( , the CIA had a sensitivity of 79.8% and a specificity of 89.5%. The RSV DFA with Bartels reagents showed a sensitivity of 94.1% and a specificity of 96.8%. For hMPV, the sensitivity and specificity were 62.5% and 99.8%, respectively, for the DHI DFA and 63.2% and 100%, respectively, for the Imagen DFA. The hands-on and test turnaround times for CIA were 10 and 30 to 60 min, respectively, and the hands-on and test turnaround times for the RSV and hMPV DFAs were 30 and 105 min, respectively. We conclude that while the RSV CIA is user-friendly, it lacks sensitivity and specificity, especially during off-peak months. In contrast, the RSV DFA is more sensitive and specific, but interpretation of its results is subjective and it demands technical time and expertise. Similarly, both hMPV DFAs are highly specific in comparison to the results of RT-PCR, but their sensitivities await further improvements.Respiratory syncytial virus (RSV) is the single most important cause of respiratory tract infections in children. It is estimated that each year in the United States, 100,000 hospitalizations and 4,500 deaths are attributed to RSV infection (20). Similar to RSV, human metapneumovirus (hMPV), identified in The Netherlands in 2001, is thought to cause upper and lower respiratory tract infections in children (23). Both RSV and hMPV are members of the family Paramyxoviridae (20). They are enveloped, single-stranded, negative-sense RNA viruses. Epidemiological studies indicate that, like RSV, hMPV is a significant human respiratory pathogen with a worldwide distribution (6,16,23,24). Indeed, hMPV appears to affect many of the same subpopulations and cause clinical manifestations, including upper respiratory tract infections, bronchiolitis, and pneumonia, similar to those caused by RSV, although they are of lesser severity (24). Both RSV and hMPV have been shown to infect the majority of children by the age of 5 years. Moreover, reinfections have been observed in all age groups (4).The laboratory diagnosis of RSV and hMPV infections can be made by virus isolation, detection of viral antigens, amplification of viral RNA by molecular techniques, demonstration of a rise in serum antibody levels, or a combination of these approaches (7,9,13,15,21,26). The use of rapid tests for the diagnosis of RSV and hMPV infections allows implementation of appropriate infection control measures, thus reducing nosocomial spread, and is useful for consideration of timely treatment with antiviral agents (8,12). The clinical and financial benefits of the rapid detection of RSV in respiratory specimens have been demonstrated in several...

Quality management in clinical microbiology began in the 1960s. Both government and professional societies introduced programs for proficiency testing and laboratory inspection and accreditation. Many laboratory scientists and pathologists were independently active and creative in expanding efforts to monitor and improve practices. The initial emphasis was placed on intralaboratory process. Later, attention was shifted to physician ordering, specimen collection, reporting, and use of information. Quality management in the laboratory depends in large part on the monitoring of indicators that provide some evidence of how laboratory resources are being used and how the information benefits patient care. Continuous quality improvement should be introduced. This consists of a more thorough assessment of doing the right things versus the wrong things in terms of customer demand and satisfaction and studying the cumulative effect of error when responsibility is passed from one person to another. Prevention of error is accomplished more through effective training and continuing education than through surveillance. Also, this system will force more conscious attention to meeting the expectations of the many customers that must be satisfied by laboratory services, including patients, physicians, third-party payers, and managed-care organizations.

A comparative evaluation of the Crystal Enteric/Nonfermenter system (Crystal; Becton Dickinson, Cockeysville, Md.), API 20E (API; bioMérieux Vitek, Inc., Hazelwood, Mo.), and the Vitek GNI card (Vitek; bioMérieux Vitek) was performed with 512 clinical isolates of gram-negative bacilli, including 381 members of the family Enterobacteriaceae and 131 nonenteric bacilli. With supplemental testing, API, Crystal, and Vitek correctly identified to the genus and species level 505 (98.6%), 489 (95.5%), and 494 (96.5%) of the 512 isolates, respectively. Supplemental testing, as specified by the manufacturer, was required to identify 119 (23.2%), 18 (3.5%), and 5 (1.0%) of the isolates with the three systems, respectively. Of the 381 isolates from the family Enterobacteriaceae, API and Crystal correctly identified 90.3 and 91.6% by 18 to 24 h without supplemental testing, respectively, and Vitek identified 92.4 and 96.1% following 10 and 18 h of incubation, respectively. Of the 131 nonenteric organisms, API and Crystal correctly identified 28.2 and 93.9% by 18 to 24 h without supplemental testing, respectively, and Vitek identified 84.0% by 10 h and 93.9% by 18 h. Errors in identification with each system were infrequent and appeared to be randomly distributed among the genera evaluated. The three systems were comparable in accuracy when either a weighted clinical laboratory profile of organisms or a group of selected isolates in a stress test sample was evaluated (P > 0.05). There were no significant differences between the three systems in their ability to identify either the isolates in the weighted group or those in the stress test (P > 0.05). Significantly more isolates required supplemental testing with API than with Crystal or Vitek (P < 0.05). Crystal compared favorably with API and Vitek, which have established track records in clinical laboratories, and is acceptable for the identification of members of the Enterobacteriaceae and nonenteric bacilli in a clinical microbiology laboratory.

Clinical laboratories do not always prepare and examine direct smears. In part, this may be explained by lack of control over the precision and accuracy of the procedure, which has diminished confidence in direct smears among both laboratory scientists and clinicians. Objective criteria were established for enumeration of cells and placement of bacteria in identification categories. Two methods for monitoring the accuracy and reproducibility of their application were studied: (1) examination of previously examined and reported direct smears of clinical specimens by independent observers with subsequent review of discrepancies with decisions by personnel; (2) preparation of suspensions of cells and bacteria that yielded identical smears for subsequent examination as unknowns. Method 1 showed agreement in bacterial identification category in 65%, quality score 74%, enumeration of neutrophils 79%, squamous cells 76%, and erythrocytes 92%. Method 2 showed that conformance of technologists' observations to expected results varied, for neutrophils conformance was 72-78%, squamous cells, 68-78%, bacterial identification category, 100%, and bacterial enumeration, 45-96%.

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