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Biomedical subjects

C G Fraser

Publications and source records attributed to C G Fraser.

At least 145 records · Page 8Linked to original sources
PubMed1981

Short- and long-term biological variation in analytes in urine of apparently healthy individuals.

Intra-individual, interindividual, and analytical components of variation for each of 10 urine analytes were estimated from results obtained on analysis of urine specimens from 10 apparently healthy young men. In spot urines, urea and osmolality showed strong individuality, but intra-individual variances were larger than interindividual variances for sodium, urate, phosphate, and glucose. Urea and osmolality displayed strong individuality in daily urines, whereas sodium (when results were expressed in output terms), urate, potassium, and total protein (when results were expressed in concentration units) had intra-individual variances larger than interindividual variances. In monthly urines, calcium and glucose, in concentration terms, and phosphate, in output terms, exhibited strongest individuality. Analytical variance was a significant percentage of the total variance for total protein and glucose; the analytical methods we used for these analytes were probably unsatisfactory. A series of analytical goals for imprecision, based on biological variation, were derived. Although these goals may not be applicable in all clinical situations, they represent the beginning of a data base in the literature.

Adult↗
PubMed1980

Comparison of standardization techniques for manual colorimetric analyses.

The influence of both the mode of standardization and the type of standard on the precision of four manual colorimetric methods performed under optimal conditions variance is described. The terms variable calibration mode and constant calibration mode are proposed; these describe standardization by within-run standards and standardization by a predetermined calibration relationship between concentration and absorbance that remains constant over a fixed period of time. We show that calibration relationships and mode of standardization must be established for each and every individual method on objective evidence. Where within-run standards are used, they must be carefully selected for each method. The implications for method evaluation and quality control are discussed.

Blood Glucose↗
PubMed1980

Goals for clinical biochemistry analytical imprecision: a graphic approach.

Analytical performance standards for the imprecision of commonly requested clinical biochemistry tests are proposed in the form of goal graphs. The goals delineated in graphic form are a consensus of published performance standards. The graphs define acceptable and unacceptable performance standards for levels of analyte commonly encountered in clinical laboratory practice. The graphic approach allows a flexible presentation of goals that is easy to interpret. The disadvantage of goal graphs is their necessarily empirical foundation.

Bilirubin↗
PubMed1980

Problems associated with clinical chemistry quality control materials.

Quality control methods and materials are widely used to monitor each and every facet of clinical chemistry laboratory performance. Quality control materials are also used in evaluation of methods and as secondary standards. A wide range of liquid and lyophilized materials are available from commercial sources and are prepared in individual laboratories. Many problems arise in the use of quality control materials. Problems discussed in this review include the use of nonhuman based materials and additives of animal origin, the physical and chemical characteristics of quality control materials that differentiate such samples from those from patients, attempts to generate quality control materials with elevated levels of particular analytes, the difficulties in handling and storage of quality control materials, the dangers of hepatitis, and the stability of quality control materials both during storage in the laboratory and after their reconstitution. The advantages and disadvantages of liquid and lyophilized quality control materials are discussed. The assignation of analyte values is of particular importance as the current trend is to consider inaccuracy of laboratory methods in addition to imprecision. This review assesses relevant publications in an area of fundamental importance to quality control in clinical chemistry.

Animals↗
PubMed1979

Rapid cholesterol measurement: patient classification in heart risk evaluation clinics.

Plasma cholesterol levels of patients attending a heart risk evaluation clinic were measured both in the clinic at the time of attendance, and later in a reference laboratory. The workflow of evaluation clinics may be improved, and patient satisfaction enhanced, by in situ measurement, since more than 60% of patients can be given a complete risk score at the time of attendance.

Cholesterol↗
PubMed1979

Assessment of the Beckman oxygen rate analyzer for the enzymatic assay of cholesterol.

We describe an evaluation of the Beckman oxygen rate analyzer for the determination of cholesterol. The precision and accuracy obtained did not fulfill the short-term criteria of the Center for Disease Control but the precision met the criteria of the College of American Pathologist for analysis of cholesterol in screening programs. Good overall correlation between the oxygen rate method and a continuous-flow method with prior extraction was found for patient samples. The results obtained by the oxygen rate method had net positive bias up to the limit of linearity of 8.6 mmol cholesterol/liter. The instrument is not recommended for laboratory or epidemiological studies but may prove useful in screening programs.

Autoanalysis↗
PubMed1979

Assessment of the Beckman creatinine analyzer 2.

An evaluation of the Beckman Creatinine Analyzer 2 has been carried out. Good day-to-day and within-day precision was obtained. Analyses of quality control materials, studies of linearity, and comparison of the results obtained for samples from patients with the results obtained by a continuous-flow method evidenced good accuracy. Aceto-acetate in serum caused significant positive interference. The desirable performance characteristics and practicability make this Analyzer attractive to the clinical chemist, particularly for paediatric and emergency laboratory use.

Autoanalysis↗
PubMed1979

A clinical view of analytical goals in clinical biochemistry.

The analytical goals inferred desirable by a group of clinicians for the imprecisions of a wide range of analytes have been studied by survey. The goals required have not in general become more stringent in the past decade and are not as demanding as those promulgated by laboratory professionals. Clinical biochemistry laboratories can now attain analytical imprecisions which satisfy the general demands of clinicians except for analyses of calcium and of low levels of glucose. The lack of published data on analytical goals does not allow wide comparison of criteria for performance standards with the results of this study.

Attitude of Health Personnel↗
PubMed1978

Evaluation of a kit for the colorimetric determination of inorganic phosphate.

An evaluation of a colorimetric kit method for the determination of inorganic phosphate (Pierce Phosphorus Auto/Stat Kit) is described. The within-batch and between-batch precisions were shown to fulfil current criteria, and recovery experiments, linearity studies, analyses of quality control materials, and studies of possible interfering substances evidenced good accuracy. Comparison of the results obtained on samples from patients with those obtained by the vanadate/molybdate continuous-flow method showed that the test method had a comparative positive bias. The use of a calibration reference serum as standard is recommended. The kit method is technically simple, requiring no protein precipitation, and analyses can be performed rapidly.

Colorimetry↗