Cost analysis of smear microscopy and the Xpert assay for tuberculosis diagnosis: average turnaround time.

INTRODUCTION: Rapid and accurate tuberculosis detection is critical for improving patient diagnosis and decreasing tuberculosis transmission. Molecular assays can significantly increase laboratory costs; therefore, the average time and economic impact should be evaluated before implementing a new technology. The aim of this study was to evaluate the cost and average turnaround time of smear microscopy and Xpert assay at a university hospital. METHODS: The turnaround time and cost of the laboratory diagnosis of tuberculosis were calculated based on the mean cost and activity based costing (ABC). RESULTS: The average turnaround time for smear microscopy was 16.6 hours while that for Xpert was 24.1 hours. The Xpert had a mean cost of USD 17.37 with an ABC of USD 10.86, while smear microscopy had a mean cost of USD 13.31 with an ABC of USD 6.01. The sensitivity of smear microscopy was 42.9% and its specificity was 99.1%, while the Xpert assay had a sensitivity of 100% and a specificity of 96.7%. CONCLUSIONS: The Xpert assay has high accuracy; however, the turnaround time and cost of smear microscopy were lower than those of Xpert.

Cost analysis of smear microscopy and the Xpert assay for tuberculosis diagnosis: average turnaround time

Abstract INTRODUCTION: Rapid and accurate tuberculosis detection is critical for improving patient diagnosis and decreasing tuberculosis transmission. Molecular assays can significantly increase laboratory costs; therefore, the average time and economic impact should be evaluated before implementing a new technology. The aim of this study was to evaluate the cost and average turnaround time of smear microscopy and Xpert assay at a university hospital. METHODS: The turnaround time and cost of the laboratory diagnosis of tuberculosis were calculated based on the mean cost and activity based costing (ABC). RESULTS: The average turnaround time for smear microscopy was 16.6 hours while that for Xpert was 24.1 hours. The Xpert had a mean cost of USD 17.37 with an ABC of USD 10.86, while smear microscopy had a mean cost of USD 13.31 with an ABC of USD 6.01. The sensitivity of smear microscopy was 42.9% and its specificity was 99.1%, while the Xpert assay had a sensitivity of 100% and a specificity of 96.7%. CONCLUSIONS: The Xpert assay has high accuracy; however, the turnaround time and cost of smear microscopy were lower than those of Xpert.

Glycerol-based sterilization bioindicator system from Bacillus atrophaeus: development, performance evaluation, and cost analysis.

The development of new value-added applications for glycerol is of worldwide interest because of the environmental and economic problems that may be caused by an excess of glycerol generated from biodiesel production. A novel use of glycerol as a major substrate for production of a low-cost sterilization biological indicator system (BIS; spores on a carrier plus a recovery medium) was investigated. A sequential experimental design strategy was applied for product development and optimization. The proposed recovery medium enables germination and outgrowth of heat-damaged spores, promoting a D (160 °C) value of 6.6 ± 0.1 min. Bacillus atrophaeus spores production by solid-state fermentation reached a 2.3 ± 1.2 × 10(8) CFU/g dry matter. Sporulation kinetics results allowed this process to be restricted in 48 h. Germination kinetics demonstrated the visual identification of nonsterile BIS within 24 h. Performance evaluation of the proposed BIS against dry-heat and ethylene oxide sterilization showed compliance with the regulatory requirements. Cost breakdowns were from 41.8 (quality control) up to 72.8 % (feedstock). This is the first report on sterilization BIS production that uses glycerol as a sole carbon source, with significant cost reduction and the profitable use of a biodiesel byproduct.

Further insight into the Bovine serum Albumin assay (the in vitro anti-inflammatory assay) / Profundización en el ensayo de Albúmina de suero bovino (el ensayo anti-inflamatorio in vitro)

The present article reports on the comparative cost of using the Bovine Serum Albumin as an assay for detecting natural products with anti-inflammatory activities relative to the use of animals. This is an addendum to the West Indian Medical Journal article; 2008; 57 (4); 327-31.

El presente artículo consiste en un reporte comparativo del costo del uso de la albúmina de suero bovino en forma de ensayo para detectar productos naturales con actividad anti-inflamatoria en relación con el uso animal. El mismo constituye un apéndice al artículo de West Indian Medical Journal, 2008; 57 (4); 327-31.

Further insight into the bovine serum albumin assay (the in vitro anti-inflammatory assay).

The present article reports on the comparative cost of using the Bovine Serum Albumin as an assay for detecting natural products with anti-inflammatory activities relative to the use of animals. This is an addendum to the West Indian Medical Journal article; 2008; 57(4); 327-31.

Comparison of a SYBR green I-based assay with a histidine-rich protein II enzyme-linked immunosorbent assay for in vitro antimalarial drug efficacy testing and application to clinical isolates.

In vitro drug susceptibility testing with the malaria parasite has been used to assess the antimalarial activities of new compounds and to monitor drug resistance in field isolates. We investigated the validity of a SYBR green I fluorescent-based assay under various culture conditions and compared the assay results to those of previously published histidine-rich protein II (HRPII) enzyme-linked immunosorbent assay (ELISA) methods. Reference strains of Plasmodium falciparum were cultured in vitro by using standard conditions in complete medium with and without phenol red before they were dispensed into 96-well plates predosed with chloroquine, mefloquine, or quinine. Following incubation, the culture supernatants were divided and the 50% inhibitory concentrations (IC50s) were determined by using a SYBR green I-based method and the HRPII capture ELISA method. There were no significant differences in IC50 values when phenol red was included in the medium. The IC50s and the IC90s of the antimalarials tested by both methods were similar or identical for each of the reference strains. Fresh clinical isolates of P. falciparum collected from imported cases of malaria in Lyon, France, were tested for in vitro resistance to chloroquine and mefloquine by using the validated SYBR green I and HRPII ELISA methods. The SYBR green I-based method was able to calculate IC50 and IC90 values similar or identical to those calculated by the HRPII assay with fresh clinical samples without removal of white blood cells. The SYBR green I-based method for determination of drug sensitivity levels produced results comparable to those produced by other methods, showing that this method can be used routinely to conduct surveillance for drug resistance in P. falciparum with fresh or cultured parasites.

[Recombinant human erythropoietin: method of in vivo evaluation using normocythemic mice]. / Eritropoyetina recombinante humana: Método de valoración in vivo con ratones normocitémicos.

PURPOSE: The implementation of an in vivo assay to determine the biological activity of human recombinant erythropoietin (Hu-r EPO) is essential. The purpose of this study was to perform and optimize the conditions of an easy in vivo bioassay suitable for routine testing of quality control of Hu-r EPO preparations. MATERIAL AND METHODS: Normocythemic 8 weeks female mice treated with different Hu-r EPO doses were employed. The reticulocyte response was measured by flow cytometry and by visual count in a Neubauer cell count chamber, after selective red blood cell haemolysis. A unique subcutaneous injection with blood extraction 96 hours later was the schedule employed. The reticulocyte count measured by both methods was plotted against the log dose of Hu-r EPO. RESULTS: The dose-response curve obtained was linear between 5 and 160 UI/mouse and the doses chosen for future assays were 10, 30 and 90 UI/mouse. The use of at least 6 animals per dose and not less than 3 assays to obtain reliable limits according to international regulations is convenient. Thirty assays were performed in four different samples and were analyzed by parallel lines (3 + 3) relating the response with the log dose. The coefficient of correlation between both methods was 0.989, so they are equivalent. CONCLUSIONS: This method is suitable because fewer animals and bioassays are necessary to obtain fiducial limits according to international requirements. It is in agreement with the tendency to reduce the number of animals used for bioassay because ethical and economic reasons.