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Biomedical subjects

C G Fraser

Publications and source records attributed to C G Fraser.

At least 127 records · Page 7Linked to original sources
PubMed1983

Short-term biological variation of plasma analytes in renal disease.

Analytical, intra-individual, and inter-individual components of variation were estimated from duplicate analyses of 11 plasma analytes in an average of 13 specimens obtained, over a two-day period, from nine patients with impaired renal function. Analytical variance was 17.3% of the total variance for sodium; less than 5% of the total variance for potassium, chloride, bicarbonate, albumin, and calcium; and less than 1% for urea, creatinine, glucose, creatine kinase (EC 2.7.3.2), and alanine aminotransferase (EC 2.6.1.2). Average intra-individual variances were of the same order as those found in healthy individuals. All analytes except glucose showed strong individuality. We postulate that, in nonacute pathological processes where new homeostatic steady states are reached, biological variations around the new set points are of the same order as those found in healthy individuals.

Autoanalysis↗
PubMed1983

Six methods for determining urinary protein compared.

Inter-laboratory surveys have shown that "routine methods" of urinary protein determination are often unsatisfactory. Therefore, we compared six frequently used methods for determination of protein in urine with respect to linearity, within-batch and between-batch precision, comparative bias, and practicability. We assayed dilutions of human and bovine albumin and serum, and fresh and lyophilized human urine. We find that the AACC Selected Method has poor practicability and poor precision under routine conditions, but good linearity. The sulfosalicylic acid/biuret technique is also impracticable, requires a large sample, and is not linear at low concentrations of urine protein. The Coomassie Brilliant Blue technique has a narrow range of linearity and poor precision. The sulfosalicylic acid/sodium sulfate turbidimetric method is not precise and cannot be standardized with bovine materials. The Ponceau-S technique has good performance characteristics and practicability, and we recommend it for routine laboratory use.

Australia↗
PubMed1982

League tables of biochemical laboratory costs. An attempt to modify requesting patterns.

"League tables", ordered by potential cost of biochemical laboratory tests requested, were distributed at four-week intervals to all medical specialists of a 500-bed tertiary care teaching hospital, Flinders Medical Centre, Adelaide, in an attempt to reduce the workload of the laboratory. This information feedback did not appear to have any effect on over-all laboratory utilisation or on any individual requesting pattern. However, much useful information on laboratory use was collated and summarised. It appears that more active intervention is required to eliminate unnecessary requesting of laboratory tests.

Biochemical Phenomena↗
PubMed1982

Comparison of standardization techniques for colorimetric analyses on a centrifugal analyzer.

The influences of the mode of standardization and the type of standard on the precision of four mechanized methods performed on a centrifugal analyzer are described. Experimental results show that the mode of standardization -- variable, using a standard in each analytical batch, and constant, using a direct relationship between concentration and absorbance -- must be objectively selected. If the variable mode is chosen, the type and level of standard must be carefully chosen and absorbance of assays of the standard must be carefully monitored for good quality control. It is recommended that the optimum standardization technique and standard, where applicable, should be assessed and subsequently documented in evaluations of methods, kits and instruments.

Centrifugation↗
PubMed1982

Components of variance of some plasma constituents in patients with myocardial infarction.

Analytical, intra-individual, and inter-individual components of variance were estimated for eight plasma analytes in 20 patients who had myocardial infarction. Replicate analyses were performed on an average of 19.5 specimens obtained from each patient over a four-day period. Analytical variance was greater than 25% of the total variance for sodium, chloride, and bicarbonate levels but less than or equal to 12% for potassium, urea, creatinine, calcium, and albumin. Sodium, bicarbonate, urea, and creatinine concentrations showed strong individuality while those of potassium chloride, calcium, and albumin did not. Estimates of average intra-individual variation were larger than those previously documented; this is probably due to variation in sample collection, transport, and handling. Analytical goals were derived from intra-individual variation but it is not recommended that these be adopted in hospital laboratories.

Adult↗
PubMed1982

A quality assurance programme for quantitative urine analyses.

Eighty-six Australasian laboratories participated in an interlaboratory quality assurance programme for 10 urine analytes. Twelve liquid samples were prepared from commercial lyophilized urine control material and distributed in 3 batches of 4. Use of pre-set acceptability limits for total laboratory error and target values facilitated timely feedback in graphic form. The samples had concentrations which were linearly related; this allowed simple calculation of overall imprecision and bias, graphic feedback of all submitted results, and comparison of performance between laboratories. A number of unsuitable and poor methods were identified. Particular attention must be paid, in future, to more widespread use of appropriate calibration and quality control materials, to avoidance of transcription and calculation errors, and to analysis of urine samples with elevated levels of analyte. Current laboratory performance can meet analytical goals for analyses of urine creatinine, phosphate, urate, and glucose but analysis of urine sodium, potassium, urea, calcium, osmolality, and proteins require a significant improvement.

Humans↗
PubMed1982

An inter-laboratory survey of qualitative urinalysis.

An inter-laboratory survey of qualitative urinalysis was carried out in Australasia during 1981. Eighty-one laboratories analysed 6 samples of urine distributed in 3 batches of 2 at regular bimonthly intervals, mostly with commercially available reagent strips. Fewer than 30% of laboratories performed any form of quality control for analytes other than pH. Results indicated that improvement in the analysis of urine bilirubin, protein, glucose, ketones and blood is required, and recommendations to improve standards are made.

Asia↗
PubMed1981

Assessment of colorimetric enzymatic determination of triglyceride, by manual and centrifugal analyzer techniques, and comparison with a CDC standardized method.

We describe the assessment of an enzymatic method, with colorimetric detection, for the determination of triglyceride. Two commercial single vial reagent sets were evaluated, by manual and centrifugal analyzer techniques, and compared to a method which had attained standardized status from the Center for Disease Control (CDC). Precision and accuracy obtained on analysis of CDC reference materials, and precision obtained on analysis of plasma samples, did not fulfill the criteria of CDC. The precision met the criteria of the College of American Pathologists based upon intra-individual variation. Good correlation between the reagent set method and a continuous-flow method with prior extraction was evident but proportional and constant biases were found. The method would be suitable for routine use particularly if a centrifugal analyzer was employed. If a manual method was used it is recommended that blanks be performed on samples. The method had acceptable linearity. Use of a constant relationship between concentration and absorbance did not lead to improved performance characteristics.

Autoanalysis↗
PubMed1981

Effect of feedback to clinical staff of information on clinical biochemistry requesting patterns.

Attempting to reduce the number of unnecessary tests requested, we initiated a program providing continuous feedback to clinicians concerning their requesting patterns of clinical biochemistry laboratory tests. At four-week intervals each medical specialist received data showing the number and costs of tests requested by all members of his team, the number of patients who had tests, and various related information. Comparative summaries, in frequency-histogram format, of the number of specimens submitted and the costs involved allowed each medical specialist to rate his own performance against that of his peers. The program appeared to have no effect on laboratory use, although reliable information concerning workload patterns was accrued. The degree of education of medical students in clinical biochemistry did not appear to influence the use they made of the laboratory after qualification. The specimens per bed-day ratio is suggested as a useful parameter in the identification of inappropriate laboratory use and as a standard parameter for comparing laboratory use in different hospitals.

Australia↗