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Biomedical subjects

G C Glenn

Publications and source records attributed to G C Glenn.

17 recordsLinked to original sources
PubMed1989

The urine chemistry survey--series 2. 5 years' experience with an interlaboratory comparison program.

We have reviewed 5 years' experience with the College of American Pathologists Urine Chemistry Survey--Series 2. Analytes studied include aldosterone, total free catecholamines, the fractionated catecholamines norepinephrine, epinephrine, and dopamine, total catecholamines, estriol, 5-hydroxyindoleacetic acid, 17-ketogenic steroids, 17-ketosteroids, vanillylmandelic acid, cortisol, metanephrines, coproporphyrin, and uroporphyrin. Interlaboratory precision achieved by participants did not reach levels reported by various investigators, but their studies do not reflect actual clinical laboratory conditions. The intralaboratory analytical precision may be adequate for clinical diagnosis but better interlaboratory agreement must await the preparation of standards verified by definitive analyses. Biases introduced by the use of many different standards probably are the origin of mediocre interlaboratory proficiency testing performance.

17-Ketosteroids↗
PubMed1983

The advanced urine chemistry survey.

A special urine chemistry survey was implemented by the College of American Pathologists during the year 1981. Ten analytes are included in this survey, including aldosterone, free catecholamines, total catecholamines, estriol, 5-hydroxyindole acetic acid, 17-ketogenic steroids, 17-ketosteroids, vanillylmandelic acid, cortisol, and metanephrines. Data obtained from 1981 and 1982 was derived from 398 subscriptions. Inadequacies in quantitative analytic methods for aldosterone, 5-hydroxyindole acetic acid, 17-ketogenic steroids, and urinary free cortisol were demonstrated. Some screening methods for 5-hydroxyindole acetic acid yielded false results.

17-Hydroxycorticosteroids↗
PubMed1980

The results of analyte enhancement and use of supplied urine protein standard on the CAP Urine Chemistry Survey Program.

Thirteen analytes were presented for participant analysis during the year 1979. Included were amylase, calcium, phosphorus, sodium, potassium, creatinine, osmolality, total protein, glucose, urea nitrogen, 17-ketosteroids, 17-ketogenic steroids, and vanillylmandelic acid. A urine protein standard was provided, and approximately half of participating labs used it. The severe biases demonstrated in past years between urine protein analytic methods was eliminated, and interlaboratory precision was greatly improved. Among labs not choosing to use the standard, poor interlaboratory precision and severe bias between methods persisted. Elevation of sodium and calcium concentration to levels simulating human disease resulted in significantly poorer analytic performance.

Chemistry, Clinical↗
PubMed1979

Quality control by blind sample analysis.

Quality control efforts may be biased consciously or unconsciously. External programs are handicapped by the time lapse before poor performance is disclosed. Bias induced into internal and external quality control efforts by special handling may be eliminated through submission of blind samples originating from wards, clinics, or phlebotomy areas. Evaluation of laboratory performance is obtained under conditions similar to those experienced by the patients' specimens. Calibration performance by operators, which varies considerably, can be monitored. Laboratory clerical activity can be scrutinized and errors quantitated and corrected. Perhaps most important, the sum of the effects of specimen handling and analytic variability can be determined.

Alkaline Phosphatase↗
PubMed1979

Evolution of the Urinary Chemistry, Survey Program of the CAP.

Thirteen analytes were presented in the Urine Chemistry Survey Program during the year 1978. These included amylase, calcium, phosphorus, sodium, potassium, creatinine, osmolality, total protein, glucose, and urea nitrogen as regular constituents. Optional analytes included 17-ketosteroids, 17-ketogenic steroids, and vanillylmandelic acid. Certain samples elevated sodium, potassium, calcium, and phosphorus concentration to stimulate human disease states and to test consensus results in ranges heretofore not possible. Serious loss of precision performance was not noted although some methods are noticeably affected. Improvement in interlaboratory precision has sllowed as compared with previous years.

Chemistry, Clinical↗
PubMed1978

The CAP Urine Chemistry Survey Program for 1977.

Eleven analytes were presented in the Urine Chemistry Survey Program during the year 1977. These included amylase, calcium, phosphorus, sodium, potassium, creatinine, osmolality, 17-ketosteroids, total protein, glucose, and urea nitrogen. More than 450 laboratories participated. Deficiencies in assay performance were found for amylase, 17-ketosteroids, and total protein. Sharp shifts in precision performance were seen in urea nitrogen analysis. Severe biases are apparent in glucose analysis using neocuproine and ferricyanide methods.

17-Ketosteroids↗
PubMed1977

Urinary chemistry. A new CAP program.

A pilot survey program for urinary chemistry was implemented by the College of American Pathologists during the year 1976. The nine analytes selected for the program were amylase, calcium, phosphorus, sodium, potassium, creatinine, osmolality, 17-ketosteroids and total protein. Data obtained from more than 230 enrolled laboratories indicate deficiencies in assay performance for amylase, 17-ketosteroids and total protein as measured by consensus evaluation. Acceptable performance was apparent for the remaining analytes.

17-Ketosteroids↗
PubMed1976

Effects of specimen evaporation on quality control.

Serum samples stored in a refrigerator and in ambient room air were studied for alteration of mean weight and mean concentration values. The storage period selected was four hours and the samples were variously stored exposed, refrigerated, and covered with a sample tray cover and by an airtight cover. Some storage procedures produced values more than 2 SD from the mean for many analytes. These findings were confirmed by a parallel study revealing a decrease of sample weight after the four-hour storage period. Storage at 4 C in sample cups covered by an airtight opaque shield alleviated the problem. Failure to treat external quality control sample pools in the same way as other samples will produce unexplained out-of-control results.

Air↗
PubMed1975

Do volunteer donors decrease posttranfusion hepattis?

A change from a paid to a volunteer blood donor system was instituted as recommended by the American Association of Blood Banks "Statement on the National Blood Policy." The incidence of counterelectrophoresis HBSAg positive units from each donor group was determined. Of 2,785 purchased units, 3 (0.10%) were HBSAg positive, while 34 (0.94%) of 3,609 units from volunteers were HBSAg positive. This 840% increase suggests that careful selection of donor population rather than blind reliance on volunteers should be emphasized in providing the safest blood for transfusion.

Blood Banks↗