Evaluation of a Plasma hCG Method for Point of Care Testing with the Aim of Shortening Test-Turnaround-Times

Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT&reg hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same patient samples. Methods: Prospective cross-sectional laboratory test evaluation. We compared plasma hCG results obtained with the i-STAT&reg hCG test (Abbott Point of Care, Princeton, NJ, USA) with Architect Ci8200 (Abbott Laboratories, Abbott Park, IL, USA). We also calculated the total coefficient of variation (CV) for the i-STAT&reg method. Results: The two methods showed a good linear correlation (R2 = 0.994;slope 1.03) and CV for the i-STAT&reg method was 2.1% - 5.2%. Conclusion: We suggest that the i-STAT&reg hCG blood assay could be used as a complement to urine hCG assays in clinical situations when rapid test results are needed and urine is not available.

A microfluidic device for accurate detection of hs-cTnI

This device is aimed at ensuring that the sample is uniformly and equivalently reacted with the antibody on the NC membrane in each test when the microfluidic liquid system is introduced to the chip.In this study,the developed microfluidic chip can avoid the presence of the sample and conjugate pads in the chip,while the precision of the chro matography system can be greatly improved using the same particles,NC membrane and antibody alongside the traditional strip.The results,taking the detection of cTnI as an example,revealed that the coefficient of variation(CV)is controlled within 4%,while the maximum record of the contrast chromatographic reagent strip can reach 15%.Additionally,the detection sensitivity can maintain the same order of magnitudes with that of the traditional chromatographic strip.With the results,the determination correlation of the developed microfluidic chip has been greatly improved.In addition,the CV of the chip in this study is greatly improved in comparison with that of the traditional strip.The biggest improvement lies in the mixing between the sample and the microspheres,indicating that this is a new approach to improve the CV of the traditional strip.

Paper Analytical Device for the Colourimetric Detection of Alkaline Phosphatase in Serum and Saliva

A paper analytical device(PAD)was developed for the colourimetric estimation of alkaline phosphatase(ALP).ALP catalyzes the hydrolysis of disodium phenyl phosphate(DSPP)to phenol,which then undergoes oxidative coupling with 4-aminoantipyrine(4-AAP)producing a reddish brown-coloured quinone imine.The colourimetric reaction tested in solution has been translated onto a PAD for the point of care(PoC)testing of ALP.A uniform colour was obtained in 25 min with the introduction of ALP onto the reagent drop cast paper device.The images obtained by scanning the PAD were processed using ImageJ software.The colour intensity obtained by image processing was proportional to the concentration of ALP present in the sample.ALP in serum and saliva samples were tested using the PAD in the range of 0 to 528 U/L and 0 to 187 U/L,respectively.The interference studies revealed that the PAD was selective to ALP in the presence of other biomolecules.The PAD exhibited a limit of detection(LOD)of 3.3 U/L and a sensitivity of 48.36 a.u/Log(U/L)for serum ALP and LOD of 1.69 U/L and a sensitivity of 28.5 a.u/Log(U/L)for salivary ALP.The PAD showed good agreement with the clinical methods for real samples.

A new quality control method for lateral flow assay

Precision and repeatability are challenging issues in point of care testing(POCT) analysis. Herein, we proposed a lateral flow assay(LFA) based on internal quality control microspheres to realize the accurate diagnosis of HbAlc in human body. Fluorescein cy5 decorated microspheres are used as labels for HbAlc detection, and BSA-fluorescein isothiocyanate(FITC) decorated microspheres are used as internal quality control labels. One test line was employed in the strip for the detection of glycosylated hemoglobin(HbAlc). This method can eliminate the interference of environmental factors(temperature, humidity,etc.) to LFA in the process of chromatography, and improve the precision and accuracy of HbAlc detection.The CV for detection of low concentration HbAlc was 1.05%, and the CV for detection of high concentration HbAlc was 0.69%. We envision the method to have great prospect in in vitro diagnosis(IVD).