We report reference intervals for IgG, IgA, IgM, C3, and C4 for a population of 750 well children and 120 healthy adults. Ranges were established by rate nephelometry (previous studies have been based on immunodiffusion). Our results generally agree with previously established immunoglobulin ranges, except for some disagreement as to ages when adult values are attained.

Comparison of serum protein electrophoresis by agarose gel and capillary zone electrophoresis in a clinical settingCapillary zone electrophoresis (CZE) offers the potential for automating serum protein electrophoretic analysis traditionally performed on standard thin-layer agarose gels. The following describes the use of CZE compared to agarose gel electrophoresis (AGE) for the detection of dysproteinemia and paraproteinemia in a clinical study involving 240 patients. The study includes within-run and between-run reproducibility data on the Paragon CZE@ 2000 Clinical Capillary Electrophoresis System, in addition to concordance data between the two methodologies. Paraprotein quantitation studies comparing AGE versus CZE were also performed. Reproducibility for the automated CZE system was superior to the AGE system. Improved reproducibility for the CZE method is largely due to measuring protein absorbance directly at 214 nm versus the traditional AGE method that measures the amount of dye adsorbed to protein. Reproducibility data as percent coefficient of variance (O/o CV) for the five classic bands in a normal control serum for between-run precision ranged from 1.2 to 4.5% for CZE compared to AGE, which ranged from 3.8 to 8.0% CV. Concordance studies between AGE and CZE involving dysproteinemias including hypogammaglobulinemia, polyclonal and monoclonal gammopathies, acute and chronic inflammation, nephrosis, hepatodegenerative disease, cirrhosis, and iron deficiency anemia showed 96% agreement. Paraprotein classification, which compared the CZE immunosubtraction method to immunofixation electrophoresis (IFE) on agarose, showed 1000/0 agreement. Certain dysproteinemias involving beta lipoprotein were in partial concordance due to the inability of the CZE procedure to detect this component. Detection limits for monoclonal gammopathies, providing they were not comigrating with other proteins, were IgG 50 mg/dL, IgM 75 mg/dL, and IgA 75 mg/dL. Paraprotein quantitative studies between the two methods showed less than a f 0.2 g/dL variation.

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The present study was undertaken to compare the nitrogen content of human feces as determined by the Kjeldahl technic and the micro-Dumas method as utilized in the automated Coleman nitrogen analyzer. The standard deviation between duplicate determinations of the same sample was 0.06% nitrogen in the case of the nitrogen analyzer and 0.02% nitrogen for the Kjeldahl method. The standard deviation between the average values obtained by each method for each sample was 0.07% nitrogen. The agreement between the two methods seemed to be independent of the nitrogen content. The apparent recovery of nitrogen by the nitrogen analyzer was found to be greater than that recovered by the Kjeldahl procedure. Factors which may be involved in this difference in recovery between the two methods are discussed.