Serum magnesium. A CAP survey--1975.

The results of the 1975 CAP Comprehensive Chemistry Survey of serum magnesium are presented. More than 1,260 laboratories participated in this survey. The most commonly used method for the measurement of serum magnesium concentrations is atomic absorption spectrophotometry. Colorimetric dye methods (Rapid-Stat (TM) kits, the Dupont ACA and titan yellow) follow in popularity. Variation in precision was lowest with atomic absorption and highest with titan yellow methods. All three of the dye-binding methods demonstrated either consistently negative or consistently positive biases when compared with the weighted mean concentration. The differences between the mean concentrations obtained by the dye-binding methods and atomic absorption spectrophotometry are statistically analyzed, and several conclusions are presented. As demonstrated by this survey and at the concentrations measured, the estimation of serum magnesium by any of the commonly used methods, except titan yellow, is clinically appropriate.

Serum lithium. A CAP survey perspective.

Lithium data from the 1975 College of American Pathologists Comprehensive Chemistry Survey program have been analyzed. The results have been organized into five method-dependent groups: four variations on emission flame spectrophotometry, and one group containing all manual atomic absorption methods. The bias observed between flame emission and atomic absorption methods was correlated with the sample mean. In addition, three paired specimens were analyzed by mean comparison. This study indicates that atomic absorption methods have a negative bias, but an apparent correlation with the sample mean indicates the probability of standardization error between the methods. This may be related to a protein depression effect and may be due to differences in viscosity between aqueous standards and serum-based samples. Both atomic absorption and flame emission methods demonstrate variability that is clinically satisfactory.

Hepatic pathology as a determinant of prognosis after portal decompression.

The status of 124 patients who had liver biopsies and underwent portal decompression was analyzed and correlated with certain clinical features and hepatic histologic findings. Child risk class, the urgency of operation, the presence of many Mallory bodies, the presence of cirrhosis and the cause of portal hypertension as determined histologically were found to correlate with prognosis. The estimate of hepatic reserve by Child risk class system and the presence of many Mallory bodies were found to have an independent predictive value. The observed differences in prognosis determined by other factors may be accounted for by variations in hepatic reserve. The presence of few or many Mallory bodies appears to be a contraindication to urgent operative portal decompression because of an exceedingly high mortality rate. In addition, the presence of many Mallory bodies regardless of Child class appears to correlate with a poor diagnosis. Since Mallory bodies may occur in all Child risk classes, preoperative liver biopsy is recommended whenever feasible to better define the actual operative risk of any portal decompressive procedure.

Mesenchymal chondrosarcomas of the head and neck.

Mesenchymal chondrosarcoma, in both osseous and extra-skeletal forms, has a decided predilection for the head and neck region. The two cases presented in this report affirm this tendency and also illustrate the capricious biologic behavior of the neoplasms as manifested by the 30 additional cases recorded in the literature. Histopathologic confusion with hemangiopericytoma is avoided by identification of the cartilage component in the mesenchymal chondrosarcoma and by the undifferentiated nature of the cellular (non-cartilaginous) component.

Computer-generated management tools for the clinical pathology laboratory: I. Throughput Report.

The Throughput Report is a computer program used to objectively measure and monitor the turnaround time of stat laboratory tests. It allows the clinical pathologist to recognize laboratory turnaround time problems prospectively. The main features are (1) a summary of the number of specimens received, accessioned, and performed per hour; (2) a histogram of the mean turnaround time per hour; (3) an overdue list of all tests taking longer than expected. Utilization of this report has decreased the percent of stat biochemical analyses taking 60 minutes or more by nearly one-half. The usefulness of the many graphic displays of work flow through the laboratory for monitoring turnaround time is discussed in detail.

Implementation of an on-line archive for retrieval of laboratory results for outpatients.

An on-line archive of laboratory results designed specifically for ambulatory care areas is described. It is a direct result of paper-flow problems in clinics, which were manifested by numerous phone calls to the laboratory for test results performed up to 10 months ago, and requiring as much as 30 minutes each for retrieval. The archive is incorporated into the result inquiry program of our laboratory computer and is transparent to the user. Utilization of this system by our personnel saves up to 12 hours of work each day. By capturing in a separate file the patient location of each call for outpatient results we are able to identify the clinics that use the telephone for retrieval of test results.