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The Canadian Society of Clinical Chemists (CSCC) and the Canadian Academy of Clinical Biochemistry (CACB) have recently implemented a new professional development program for its 400 members. The program's goals are: to evaluate and recognize professional development based on self-determined needs, interests, and learning preferences; and to ensure that qualified professionals directing clinical biochemistry laboratories have adequate basic and current knowledge to function competently in their profession. Involvement in the program is currently voluntary and based on a 3-year cycle during which time participants must earn a minimum of 150 credits from at least 3 of 8 categories' learning activities. Of these activities: four are related to updating knowledge (Formal Group Learning related to Laboratory Medicine, Other Formal Group Learning, Self-Directed Learning, Self-Assessment); three are related to the maintenance and implementation of practice skills (Service Associated Learning, Teaching, Change in Practice); and one is related to the advancement of knowledge (Publications and Presentations). One credit is defined as one hour of continuing professional development activity. At the end of each year, members document their activities by submitting a 4 page Annual Summary of Activities (ASA) form. The cost of coordinating the program is minimal as it is administered by a steering committee and smaller working committees, all of whom are voluntary. A basic assumption of our program is that self-management of professional development (PD) is an important prerequisite and indicator of maintenance of competence. By recognizing learning through a number of activities and outcomes, it is anticipated that our program will promote an overall improvement in the quality of Laboratory Medicine throughout Canada.

Reaction conditions for determining the activity of purine nucleoside phosphorylase (PNP; E.C. 2.4.2.1) were investigated. We examined the kinetic parameters for the enzymatic reaction with respect to the substrates inosine and phosphate. We confirmed the pH optimum, established the optimal concentration of xanthine oxidase and that of calcium and magnesium. The Km values for inosine and phosphate were found to be 60 uM and 667 uM, respectively. Optimum assay conditions for PNP activity were established. This optimized method has been compared with other procedures and found to be more sensitive and to yield significantly higher activities. The experimental variation of a manual procedure using these optimum reaction conditions was less than 4.5%. The mean erythrocyte PNP activity of 28 healthy subjects was estimated to be 9.71 U/mL packed cells at 25 degrees C and 18.60 U/mL packed cells at 37 degrees C.

We have compared the specific gravity (S.G.) determined by the N-Multistix method with that obtained from the Total Solids (TS) meter. Overall, 88.7% of the specific gravity results obtained with the reagent strip method were within 0.005 of those obtained with the TS meter. There was a good correlation between the methods and there was no bias for the group means obtained by either method. A good correlation was also found between the S.G. on the strip and osmolality (correlation coefficient of 0.955). The results obtained with the reagent strip for urinary specific gravity therefore appear acceptable for routine laboratory purposes.

Reaction rate studies were carried out on various specimens using two commercial enzymatic cholesterol determination reagent kits (BMC and Worthington). The time required for complete colour formation differed between the two reagent systems and each kit required different incubation times for the standards and specimens to come to color completion. The choice of standards was found to be very important when using these enzymatic kits.

A new colorimetric procedure for the determination of purine nucleoside phosphorylase (PNP, E.C. 2.4.2.1) activity is described. In this procedure, the hydrogen peroxide formed in the PNP-xanthine oxidase reaction is used to oxidize the chromogenic reagents--3,5-dichloro-2-hydroxybenzenesulfonic acid/4-aminophenazone using the enzyme peroxidase. The rate of enzyme reaction is followed at 520 nm. This procedure correlated well with the UV method (290 nm), with a correlation coefficient of 0.98 (P less than 0.005). Within-run and between-run precision (CV) were less than 2.8% and 3.7%, respectively. Here we also describe an optimized NAD-dependent method (340 nm) for PNP determination. The colorimetric method is superior to both the 340 nm and the UV methods in terms of both sensitivity and precision. The mean erythrocyte PNP activity for 17 healthy subjects was 11.88 U/mL packed cells for the NAD-dependent method and 13.22 U/mL packed cells for the colorimetric method.

A simplified method is presented to estimate reference ranges from hospital laboratory data. It is based on a combination of graphical estimation of relative sizes of normal and abnormal populations and the "mode-center" concept in which the mode of the total population centers on the 50% cumulative frequency of the normal population. This method can be applied to determine reference ranges even though the data source contains abnormally high and/or low values. The reference ranges obtained for BUN and calcium from in-patient and out-patient sources by this method were found to be similar to those reported for "healthy" subjects.

Many clinical laboratories use the Beckman Microzone electrophoretic system (Beckman Instruments Inc. Fullerton, CA 92634) for serum protein separation. Although detailed instruction is supplied in the manufacturer's manual (1) for protein separation, the effect of different sample application positions on the cellulose acetate membrane is not discussed. We have processed the serum specimen in various application positions and found that there is a definite relationship between the resolution of fractionated protein bands and the application position, particularly with specimens from patients with monoclonal gammonpathies. The resolution of the protein bands increases as the sample is applied closer to the anode end of the cellulose acetate strip. Although studies were carried out on the Beckman electrophoretic system, a similar application effect may be anticipated with other electrophoretic systems.

We report here our experience with Boehringer Mannheim GOD/PAP (Trinder) glucose kit on Autonanalyzer I and SMA 12/60 systems. With slight modification on the existing procedures, we are able to obtain an efficient method that yields satisfactory results with very low cost.

The usefulness of a stick test for detection of leukocyte esterase activity in urine as part of a "macroscopic screen" was examined, as well as the efficiency of our existing broad screening criteria for detecting abnormalities in urine without microscopic examination. In a study of 923 unselected urine samples submitted to the laboratory, a false-negative rate of 0.6% was observed as judged by microscopic examination. The results of our present studies tend to confirm the usefulness of our "screen" program. The new leukocyte esterase test has been demonstrated to be an important adjunct to the macroscopic screening program.

Interest has recently been shown in the use of serum cholinesterase levels as a marker for chronic organophosphate insecticide exposure. Interpretation of the results must, however, take into account both long-term biological and analytical variations. The intraindividual variation of serum cholinesterase activity for 12 laboratory workers was 4.3%. The variation was much smaller than the interindividual variation of the whole population (20%). Based on the homogeneity of the intraindividual variance, it is possible to show the level of minimal decrease in enzyme activity which constitutes a departure from "normal".

We describe a "one-minute" direct bilirubin procedure using the ABA-100. The procedure correlates well with the manual Jendrassik-Grof method and gives good precision at a relatively low direct bilirubin level. In comparison with certain other Abbott ABA-100 direct bilirubin methods, the proposed procedure appears to be the least affected by the presence of high unconjugated bilirubin levels.

We have investigated the effect of urine pH on the simple solubility test for myoglobinuria and found that the sensitivity of the test is very pH dependent. As much as a 10 fold increase in sensitivity can be obtained if the test is performed at pH 7.5 instead of pH 5.5. As such, we recommend that the urine pH should first be adjusted within the range 7.5--8.0 before performing the solubility test for myoglobinuria.

Reaction rate studies were carried out on various quality control specimens using a ferrozine iron determination kit. The time required for complete color formation differed among the various materials tested. Quality control materials of bovine origin required a much longer incubation time for full color formation. Using a fixed incubation procedure, the bovine controls would give a falsely low result. The present study suggests that caution is indicated when quality control data using bovine materials are interpreted.