Point-of-care Testing Systems Research Articles

Reliability of international normalised ratios from two point of care test systems: comparison with conventional methods

Design Comparison of the INRs from the two systems with a “true” INR on a conventional manual test from the same sample of blood.Setting 10 European Concerted Action on Anticoagulation...

Field-testing and validation in a primary care setting of a point-of-care test for C-reactive protein.

Use of point-of-care testing (POCT) in primary care has increased. There is a need for high-quality field evaluation of POCT before deployment can be considered. A POCT system for C-reactive protein was evaluated in a routine general practice setting. The standard laboratory method was a dry slide method based in a routine hospital laboratory. Scatterplots for both venous and capillary blood POCT system results versus the standard laboratory assay produced correlation coefficients of greater than 0.96. Bland-Altman plots indicated that 95% of venous and capillary POCT results fell within +/-10 mg/L of the mean value with no clinically significant difference from laboratory results. The POCT system performed reliably in a routine general practice setting with satisfactory performance against an accepted laboratory method.

Accuracy of point-of-care-testing (POCT) for determining hemoglobin concentrations.

While point-of-care testing (POCT) is being used increasingly as a basis for deciding on perioperative erythrocyte transfusion, no valid standards currently exist concerning the accuracy of Hb concentration measurements. For clinical employment, however, the confidence limits (+/-2 SD) of these measurements should lie close to 5 g/l. The aim of the present study was to evaluate the accuracy and precision of point-of-care testing for blood hemoglobin concentration (cHb in g/l) measurements in critically ill patients. Fifty blood samples from 50 postoperative patients requiring intensive care treatment were withdrawn from a cannula in the radial artery into a 2-ml heparinized syringe (containing wet sodium heparinate in the conus), in a 2-ml Monovette with 50 IE lithium heparinate, and into a 2.7-ml cuvette with 1.6 mg potassium EDTA/ml blood. The POCT battery consisted of two blood gas analyzers (ABLTM 625 and 725, Radiometer, Copenhagen), the HemoCue system (Mallinckrodt Medical, Germany), and an automated hematology analyzer (M-2000(R), Sysmex, Germany). The cyanmethemoglobin method served as the reference 'gold standard' procedure. The blood gas analyzer and HemoCue systems were tested using dry and wet heparinized blood samples. Hemoglobin concentrations of the reference measurements ranged from 73.9 to 159.4 g/l. The automated hematology analyzer method did reveal a small but systematic deviation for higher cHb values. For the blood gas analyzer and HemoCue system procedures there was no systematic deviation of bias for either the first measurement or the averaged data. Bland & Altman analysis revealed a larger scattering for the wet heparinized samples. The above-stated requirement for POCT systems, i.e. that the confidence limits should lie close to 5 g/l cHb, held true for the dry heparinized samples of the blood gas analyzer (1st measurement and mean of 2), the HemoCue system (mean of 3) and the automated hematology analyzer.

POCT System in the Market of Genetic Diagnosis : Genetic Diagnosis by Using the Bedside ICAN Method(<Special Issue>Micro-Machine Technology and Point of Care Testing (POCT))

POCT System in the Market of Genetic Diagnosis : Genetic Diagnosis by Using the Bedside ICAN Method(<Special Issue>Micro-Machine Technology and Point of Care Testing (POCT))

Minimum numbers of fresh whole blood and plasma samples from patients and healthy subjects for ISI calibration of CoaguChek and RapidPointCoag monitors.

The international sensitivity index (ISI) calibration of point-of-care-test (POCT) prothrombin time (PT) whole blood monitors is complex, requiring manual PT testing of 60 patients' and 20 healthy subjects' plasma samples. The possibility of reducing these numbers was studied by a Monte Carlo Bootstrap study for 2 POCT PT systems. For reduced sample numbers, this consisted of 50,000 calibrations using whole blood and plasma samples tested on the monitors with manual PT testing of plasma samples from the same blood donations. There was little effect on mean ISI by reduction of sample numbers to a total of 7, but there was progressively less certainty regarding the reliability of the calibration. Precision of the calibrations and international normalized ratio deviation were not affected markedly by reducing numbers to half As ISI calibration with the 2 POCT systems was less precise than conventional manual testing, for maximum confidence, reduction of numbers is not advised.

European Concerted Action on Anticoagulation. Use of Plasma Samples to Derive International Sensitivity Index for Whole-Blood Prothrombin Time Monitors

To simplify International Sensitivity Index (ISI) calibration, the possibility of substituting fresh plasma for fresh whole-blood samples with point-of-care testing (POCT) whole-blood monitors was investigated in a three-center study of three different POCT systems. A modified full WHO calibration procedure based on 20 healthy controls and 60 coumarin-treated patients was performed on three monitoring systems with whole-blood and plasma samples against plasma tested using the European Concerted Action on Anticoagulation (ECAA) rabbit reference plain thromboplastin and the manual prothrombin time (PT) method. With one of the three systems, the mean ISI was 1.51 for whole blood and 1.49 for plasma; with the second system, the mean ISI was 1.08 for both whole blood and plasma. With the third system, however, the difference between the mean ISI for whole blood and that for plasma was greater (1.15 and 1.01, respectively). Overall, the precision of the calibrations was less than with traditional manual plasma PT testing. Provided that an appropriate calcium chloride concentration is used, the plasma PT results can be used for accurate ISI calibration of two of these three whole-blood POCT systems. Precision criteria need to be modified for POCT monitors.

European Concerted Action on Anticoagulation

A procedure for using citrated fresh plasmas for International Sensitivity Index (ISI) calibration of two types of whole blood point-of-care test (POCT) prothrombin time (PT) monitor systems has been assessed in a multicentre study. The CoaguChek Mini and TAS PT-NC systems gave higher ISI with whole blood samples than with fresh plasma calibrations. However. there was good agreement between whole blood and fresh plasma monitor system International Normalised Ratio (INR) and the reference INR of target samples. Reliable INR can therefore be obtained with both whole blood and plasma samples on these two POCT systems based on their respective ISI. With the CoaguChek Mini system, the plasma calibration ISI can also be used to derive reliable INR with whole blood PT results. This was not possible with the TAS PT-NC system.

Laboratory Process Improvement Through Point-of-Care Testing

In the 1992-1996 period Methodist Clinical Laboratory Services of the Methodist Health Group, Indianapolis, was restructuring all work processes. In one initiative, point-of-care testing (POCT) was used to optimize the decision cycle time while reducing the overall cost of providing information. DEVELOPING THE COMPARATIVE MODEL: In a typical month (May 1994) for hospital admissions and laboratory usage, events related to the traditional blood analysis process were observed. In March 1995 the same model that was applied to analyze the traditional blood analysis process was used to evaluate the newly implemented POCT blood analysis process. Comparisons of both processes, cost per test panel, nursing time spent, and overall turnaround time were made between the two methodologies. A restructure of delivery of blood analysis with the POCT system saved the hospital $392, 336 compared to the total annual cost of the traditional approach for delivering blood analysis. The average cost per test panel was $15.33 with the traditional model and $8.03 with the POCT system. Improvements in the overall turnaround time of test results affected the decision cycle time of the caregiver. The POCT system saved four steps on the patient care floor and ten in the laboratory. It is critical to establish a POCT committee, including the most vocal critics of POCT1-to look at how a program of this nature will affect the organization. POCT became more than just an isolated change-it became a core strategy of moving laboratory testing out of the traditional laboratory setting to where it could become immediately accessible to caregivers as information.