ABSTRACT
BACKGROUND: Stool microscopy and concentration techniques are the two most important and necessary aspects of diagnostic parasitology. In an era when there is increased disease burden due to intestinal parasites, an early and appropriate diagnosis is warranted. Direct microscopy is usually labor intensive and tedious. MATERIALS AND METHODS: Thirty-two fresh fecal specimens from patients presenting with eosinophilia and/or anemia (hemoglobin levels <10 g%), HIV-positive patients, and in patients clinically suspected of harboring parasites, were collected for the study. All the positive samples were processed by both the standard methodology, i.e., formalin-ethyl acetate sedimentation technique and Mini Parasep® SF method, by the standard operating procedure of our laboratory and the manufacturer's instruction. Stool pellet concentrates were subjected to saline/iodine wet mount, modified acid fast staining for intestinal coccidian parasites and trichrome staining for Blastocystis hominis. The average number of organisms counted in 0.5 ml of pellet was used for comparison of the two techniques. RESULTS: The morphology of eggs was maintained in both the techniques; however, the wet mount prepared from the sedimentation technique had more background fecal debris in comparison to the Parasep® technique. The parasite yield was equal for both the techniques while Mini parasep had the advantage of less distortion of parasite morphology. CONCLUSION: We found that Parasep® offered a better parasitic yield, a better workflow capacity, and a reduced turnaround time, which would further benefit resource-restrained laboratories and those with a high sample turnover.
ABSTRACT
Providencia rettgeri (P. rettgeri) is an ubiquitous organism but is seldom associated with human disease. We report the isolation of P. rettgeri from the urine sample of a 39-year-old male patient on prolonged Foley's catheterisation following a severe head injury. Identification of this organism was done by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF) based systems. P. rettgeri is an emerging pathogen among long term catheterised patients. It reflects its ability to form biofilm on the surface of the indwelling catheter as well as the inherent urease producing property of the pathogen in question as a possible mechanism of pathogenesis.
ABSTRACT
INTRODUCTION: Antibodies to Hepatitis B surface Antigen (Anti-HBs) levels are measured as markers for immune response to vaccination and in decision making for post-exposure prophylaxis against Hepatitis-B. Several immunoassay formats are used to measure Anti-HBs, thus carrying the possibility of variation in measured levels between different assays. This study compares the performance of Chemiluminescence Immunoassay (CLIA) against Enzyme-linked Immunosorbent Assay (ELISA) in measuring Anti-HBs titer by looking into concordance between the two test reports. AIM: To compare the agreement between ELISA and CLIA in measurement of Anti-HBs antibody titers. MATERIALS AND METHODS: This prospective comparative study conducted at Kasturba Medical College, Manipal measured consecutive serum samples (69) sent for anti-HBs levels during May-June 2016 using both CLIA (Abbott Architect) and ELISA (Bio-Rad). Anti-HBs values of ≤10mIU/ml was considered as non-protective and >10mIU/ml as protective. The agreement between the tests in classifying the antibody titers as non-protective or protective was computed using Kappa coefficient, and the difference in individual titer values between the tests compared using Bland-Altman plot on SPSS (v.15). RESULTS: Out of the 69 samples analysed, 18 samples (26.1%) were of health-care personnel and remaining of patients. Agreement between ELISA and CLIA in identifying the antibody titers as protective and non-protective were 96.5% and 90.9% respectively, resulting in an agreement of 0.84. The coefficient-of-variation of ELISA and CLIA were 74.5% and 113.1%, respectively. Three value based discordant results were noted; two samples deemed protective by ELISA were reported as non-protective by CLIA. One non-protective titer by ELISA was reported as protective by CLIA. CONCLUSION: Analytical agreement is good between the two immunoassays. However there are some discrepancies in quantitative measurement. This may have been due the variation in the standard calibrators used in each assay. Though CLIA showed more variation in the values, it has the advantage of being automated test with low turn around time. Therefore, both the test methodologies can be reliably used in place of each other for detection of Anti- HBs titer.
