An evaluation and comparison of Reflolux II and Glucometer II, two new portable reflectance meters for capillary blood glucose determination.

The Reflolux II and the Glucometer II, two new battery-operated portable reflectance meters (PRMs) for blood glucose measurement have been evaluated for accuracy, precision and ease of operation. Both PRMs are pocket-size and simple to use. The calibration of the two instruments is fundamentally different, but in both cases the calibration data are provided with the reagent test strips and require minimal operator participation. The analysis time is 50 s for the Glucometer II and 120 s for the Reflolux II. The Reflolux II has a measuring range of 0.5-27.7 mmol/l, which is superior to the 2-22 mmol/l range of Glucometer II. Both PRMs had excellent correlation (r greater than 0.97) and minimal bias when compared by regression analysis to a laboratory method on capillary and whole blood samples. The precision of the Reflolux II was marginally better than the Glucometer II with coefficients of variation less than 6.57% for the Glucometer II and less than 5.21% for the Reflolux II. Neither the Reflolux II nor the Glucometer II offer significant advantages one over the other, both are adequate for their designed use, and both are distinct improvements over their predecessors.

Comparison of Chemcard cholesterol test and laboratory cholesterol measurements.

BACKGROUND: The Chemcard cholesterol test has been designed to estimate cholesterol levels in patients in General Practitioners' surgeries. The patients displaying elevated cholesterol levels may then be referred for a more accurate test at a recognised laboratory. AIMS: To compare the accuracy of the Chemcard cholesterol procedure with a standardised laboratory procedure for estimating cholesterol levels. METHODS: The Chemcard cholesterol procedure was applied to 200 subjects from the community, who were enrolled in a cardiovascular risk assessment programme. RESULTS: The correlation coefficient between the paired measurements was 0.83. The Chemcard cholesterol procedure gave slightly higher results than did the laboratory procedure as shown by the mean (+/-standard deviation) difference between the two methods of 0.16 +/- 0.58 mmol/L. CONCLUSIONS: The poor agreement between the two methods and the potential misclassification by Chemcard suggests that the Chemcard is not a reliable test system. The high level of risk group misclassification found in this study refutes the manufacturer's claims and does not eliminate the need for formal laboratory cholesterol measurement.

Measurement of sodium valproate in serum by direct-insertion chemical-ionization/mass spectrometry.

To quantitatively determine sodium valproate, we use a stable isotope-labeled internal standard and chemical-ionization/mass spectrometry, without prior chromatographic separation. The technique is rapid, simple, sensitive, and provides for the routine analysis of 100 microL of serum with good within-day and day-to-day precision. The technique also allows for the simultaneous determination of phenobarbital, mephobarbital, carbamazepine, primidone, and phenytoin.

Improved estimation of fructosamine, as a measure of glycated serum protein, with the Technicon RA-1000 analyzer.

We present an improved fructosamine assay for use with the Technicon RA-1000 analyzer. Features of this assay include: specimen throughput of 100 per hour, within-batch CV of 1.5%, between-batch CV of 2.4%, standard curve linear up to 24.9 mmol of fructosamine per liter, and good correlation (r = 0.82) with hemoglobin A1.

Separation of tryptophan metabolites by reversed-phase high-performance liquid chromatography with amperometric and fluorescence detection.

An isocratic method for the separation of most of the tryptophan metabolites in the oxidative degradation pathway is described. The chromatographic analysis utilizes the combined selectivity and sensitivity of amperometric and fluorimetric detection. The effect of pH, ionic strength and operating potential on retention times and detector responses are evaluated. The use of dual electrochemical cells at two operating potentials together with a programmable fluorescence detector allows for improved selectivity for the detection of metabolites. The sensitivity achieved with this method allows for the detection of the metabolites in biological fluids at the picomole level. The method has been used to monitor serum samples obtained during a tryptophan load test.

Quality control of portable reflectance meter capillary blood glucose results by measurement of glucose on filter paper.

The capillary blood glucose (CBG) estimated by some of the most frequent users of portable reflectance meters (PRMs) were assessed using blood applied to Whatman 31 ET filter paper at the time of the performance of the CBG. The performance of nursing staff on hospital wards, community groups screened for diabetes and patients exercising self monitoring of blood glucose (SMBG) at home were evaluated. The glucose was extracted from the filter paper with 5% trichloroacetic acid (TCA) and analyzed within 5 days of collection on a Technicon RA-1000 analyzer using Merck glucose dehydrogenase reagents. Of the 1255 samples collected, 385 were rejected due to inadequate sample collection, and a further 196 were rejected as they were received more than 5 days after collection, the time interval allowed for glucose stability on the filter paper. The CBGs obtained by the nursing staff were 2.2 - 17.1 mmol/l with a mean of 7.6 mmol/l; the community screened subjects CBGs were 1.5 -22.4 mmol/l with a mean of 5.2 mmol/l; and the SMBG users at home obtained CBGs of 1.0 - 15.1 mmol/l with a mean of 5.07 mmol/l. Of the 674 samples analyzed only 36.6% were within 10% of the laboratory blotting paper glucose (BPG) result. An alarming 35.8% exceeded 20% and 10.2% exceeded 50% of the BPG result. The correlation of all 3 groups with the BPG obtained by the laboratory were similar (correlation coefficient = 0.86, 0.85, 0.87 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)