Comparison of a parasite lactate dehydrogenase-based immunochromatographic antigen detection assay (OptiMAL) with microscopy for the detection of malaria parasites in human blood samples.
Microscopic examination of blood smears remains the gold standard for malaria diagnosis, but is labor-intensive and requires skilled operators. Rapid dipstick technology provides a potential alternative. A study was conducted in The Gambia to compare the performance of OptiMAL, an immunochromatographic antigen detection assay for the diagnosis of malaria using parasite lactate dehydrogenase, against standard microscopy in patients with suspected malaria. For initial diagnosis of Plasmodium falciparum, irrespective of stage, this assay had a sensitivity of 91.3%, a specificity of 92%, a positive predictive value of 87.2%, and a negative predictive value of 94.7%. The sensitivity of the test decreased markedly at parasitemias < 0.01%. This assay can be used for the diagnosis of malaria in areas where microscopy is not available and for urgent malaria diagnosis at night and at weekends, when routine laboratories are closed and when relatively inexperienced microscopists may be on duty. (+info)
Comparison of five methods of malaria detection in the outpatient setting.
In eastern Africa where 90% of the malaria is due to Plasmodium falciparum, the accuracy of malaria diagnosis at the outpatient level is becoming increasingly important due to problems of drug resistance and use of alternative, costly antimalarial drugs. The quantitative buffy coat (QBC) technique, acridine orange staining with an interference filter system, and the ParaSight-F test have been introduced as alternative methods to conventional microscopy for the diagnosis of malaria. Two hundred thirteen outpatients were tested using these alternative methods and conventional microscopy by five experienced technologists; two were randomly allocated to read the results of each test. Paired results showed the highest level of agreement with the ParaSight-F test (99%), followed by Field stain (92%). The results of the QBC technique showed the least agreement (73%). Using conventional microscopy as the reference standard, the ParaSight-F test had a sensitivity range of 90-92% and a specificity of 99%, staining with acridine orange had a sensitivity range of 77-96% and a specificity range of 81-98% and the QBC technique had a sensitivity range of 88-98% and a specificity range of 58-90%. All microscopic tests showed lower sensitivities (as low as 20% using staining with acridine orange) in detecting low parasitemias (< or = 320/microl) than the ParaSight-F test (70%). Due to the high cost of the ParaSight-F test, Field-stained blood films remain the most appropriate method for diagnosis of P. falciparum in eastern Africa. The ParaSight-F test may be used in situations where no trained microscopists are available, or where malaria is strongly suspected and the results of microscopy are negative. (+info)
Renal assessment practices and the effect of nurse case management of health maintenance organization patients with diabetes.
OBJECTIVE: To examine baseline renal screening practices and the effect of nurse case management of patients with diabetes in a group model health maintenance organization (HMO). RESEARCH DESIGN AND METHODS: We performed both 1-year retrospective and 1-year prospective studies of renal assessment practices and ACE inhibitor usage in a cohort of 133 diabetic patients enrolled in a randomized controlled trial of a diabetes nurse case management program in a group model HMO. In accordance with American Diabetes Association recommendations, urine dipstick and quantitative protein and microalbuminuria testing rates were calculated. RESULTS: At baseline, 77% of patients were screened for proteinuria with dipsticks or had quantitative urine testing. Of patients with negative dipstick findings, 30% had appropriate quantitative protein or microalbumin follow-up at baseline. Baseline ACE inhibitor usage was associated with decreased follow-up testing (relative risk = 0.47). Nurse case management was associated with increased quantitative protein or or microalbumin testing and increased follow-up testing (relative risk = 1.65 and 1.60, respectively). CONCLUSIONS: We found a higher degree of adherence to recommendations for renal testing than has been reported previously. Nurse case management intervention further increased renal screening rates. The inverse association between ACE inhibitor usage and microalbumin testing highlights a potentially ambiguous area of current clinical pathways. (+info)
A comparative evaluation of Etest and broth microdilution methods for fluconazole and itraconazole susceptibility testing of Candida spp.
The Etest strip is a promising tool of broad application in clinical microbiology. The method provides MIC readings and is easier to perform than broth microdilution. We carried out a study to compare the MICs of fluconazole and itraconazole obtained by the Etest with those obtained by broth microdilution, performed according to the guidelines of the NCCLS document M27-A, with 402 clinical isolates (360 Candida albicans, 17 Candida tropicalis, nine Candida krusei, nine Candida glabrata and seven Candida parapsilosis) and seven control isolates. The agreement between MICs by the two methods (at +/- 2 dilutions) was 74.5% for fluconazole and 61.4% for itraconazole. These results suggest that further development is necessary to standardize the medium and incubation conditions before introduction of the Etest as a routine method in the clinical microbiology laboratory for fluconazole and itraconazole susceptibility testing. (+info)
Validity of interpretation criteria for standardized Western blots (immunoblots) for serodiagnosis of Lyme borreliosis based on sera collected throughout Europe.
Western blotting (WB; immunoblotting) is a widely used tool for the serodiagnosis of Lyme borreliosis (LB), but so far, no generally accepted criteria for performance and interpretation have been established in Europe. The current study was preceeded by a detailed analysis of WB with whole-cell lysates of three species of Borrelia burgdorferi sensu lato (U. Hauser, G. Lehnert, R. Lobentanzer, and B. Wilske, J. Clin. Microbiol. 35:1433-1444, 1997). In that study, interpretation criteria for a positive WB result were developed with the data for 330 serum samples (from patients with LB in different stages [n = 189] and from a control group [n = 141]) originating mostly from southern Germany. In the present work, the interpretation criteria for strains PKo (Borrelia afzelii) and PBi (Borrelia garinii) developed in the previous study were reevaluated with 224 serum samples (from patients with LB in different stages [n = 97] and from a control group [n = 127]) originating from throughout Europe that were provided by the European Union Concerted Action on Lyme Borreliosis (EUCALB). De novo criteria were developed on the basis of the reactivities of the EUCALB sera and were evaluated with the data for the samples from southern Germany. Comparison of all results led to the following recommendations: For WB for immunoglobulin G (IgG), at least two bands among p83/100, p58, p43, p39, p30, OspC, p21, p17, and p14 for PKo and at least one band among p83/100, p39, p30, OspC, p21, and p17b for PBi; for WB for IgM, at least one band among p39, OspC, and p17 or a strong p41 band for PKo and at least one band among p39 and OspC or a strong p41 band for PBi. WB with PKo was the most sensitive, and this strain is recommended for use in WB for the serodiagnosis of LB throughout Europe. (+info)
Evaluation of the pathotec Rapid I-D system for identification of Enterobacteriaceae.
The PathoTec Rapid I-D System for identifying Enterobacteriaceae was evaluated with 471 cultures. In 4,910 individual test comparisons, 95.5% of the results agreed, with results of only two test strips, those for esculin hydrolysis and urease production, agreeing with conventional tests in less than 94% of the trials. The PathoTec system exhibited 94.3% accuracy in identifying these cultures in a double-blind study with conventional media and procedures as the alternate system. Two newly developed test strips, for 0-nitrophenyl-beta-D-galactopyranoside and ornithine decarboxylase, were found to be highly reliable. (+info)
Evaluation of a rapid and inexpensive dipstick assay for the diagnosis of Plasmodium falciparum malaria.
Rapid, accurate and affordable methods are needed for the diagnosis of malaria. Reported here is an evaluation of a new immunochromatographic strip, the PATH Falciparum Malaria IC Strip, which is impregnated with an immobilized IgM monoclonal antibody that binds to the HRP-II antigen of Plasmodium falciparum. In contrast to other commercially available kits marketed for the rapid diagnosis of falciparum malaria, this kit should be affordable in the malaria-endemic world. Using microscopy and polymerase chain reaction (PCR)-based methods as reference standards, we compared two versions of the PATH test for the detection of P. falciparum infection in 200 febrile travellers. As determined by PCR and microscopy, 148 travellers had malaria, 50 of whom (33.8%) were infected with P. falciparum. Compared with PCR, the two versions of the PATH test had initial sensitivities of 90% and 88% and specificities of 97% and 96%, respectively, for the detection of falciparum malaria. When discrepant samples were retested blindly with a modified procedure (increased sample volume and longer washing step) the sensitivity and specificity of both kits improved to 96% and 99%, respectively. The two remaining false negatives occurred in samples with < 100 parasites per microliter of blood. The accuracy, simplicity and predicted low cost may make this test a useful diagnostic tool in malaria-endemic areas. (+info)
Evaluation of the one-minute ultra-rapid urease test for diagnosing Helicobacter pylori.
To determine the diagnostic accuracy of the one-minute ultra-rapid urease test for diagnosing Helicobacter pylori infection, two biopsies were taken from both the gastric corpus and antrum from 1000 patients undergoing upper gastrointestinal endoscopy. All the biopsies were subjected to the one-minute ultra-rapid urease test before imprint smears were prepared from them. Thereafter, the biopsies were fixed in 10% formalin and histological sections were examined for the presence of H pylori by a pathologist who was not aware of the clinical details or the results of the urease test. The prevalence of H pylori in the gastric antrum and corpus was 86.7% and 53.3%, respectively. The sensitivity, specificity, positive and negative predictive value and the overall diagnostic accuracy of the ultra-rapid urease test to diagnose H pylori infection in the gastric antrum were 92%, 100%, 100%, 66%, and 93%, respectively. The corresponding figures for the gastric corpus were 83%, 100%, 100%, 85%, and 91%, respectively. It is concluded that the one-minute ultra-rapid urease test has a high sensitivity and specificity and may be used as a rapid and cheap method to diagnose H pylori infection. (+info)