A triclonal gammopathy is an immunoglobulin abnormality in which three discrete monoclonal subpopulations of immunoglobulin molecules are present in a patient's serum. Monoclonal and biclonal gammopathies have been studied extensively, but relatively little is known about the much rarer triclonal gammopathies. The case described below illustrates some of the difficulties that this condition can present to the clinician and the clinical laboratory.

The Beckman Array and the Behring Ne-meter offered a choice of single or multiphelometer offer the clinical laboratory point calibration, retrieval of raw data, ease completely automated discrete protein of operation, more flexibility in test paramanalysis. To select one of these systems, eters, and choice of calibrator. Interferwe compared five protein analytes: IgG, ence from lipemia frequently caused IgA, IgM, transferrin, and prealbumin. In variable results requiring pretreatment of addition to automation, we wanted to the sample. Both instruments demonachieve better precision than our present strated excellent precision, linearity, and method and have available a wider range correlated adequately with the Hyland of test selection. The Beckman Array gave Laser Nephelometer PDQ. The Array dem-2-week stability of calibration, analyzed li-onstrated slightly better slope values than pemic samples without significant prob-those of the Behring Nephelometer with lems, and had direct manufacturer's the exception of prealbumin analysis. service available. The Behring Nephelo

Owing to the generally higher values observed in the initial establishment of immunoglobulins (Ig) G, A, and M assays with the Behring Nephelometer, we elected to verify five commercial protein calibrators. This initial verification was performed by standardizing the Behring Nephelometer with the World Health Organization (WHO) International Reference Preparation for Human Serum Immunoglobulins G, A, and M. The instrument was also standardized for immunoglobulins and transferrin with use of the Reference Preparation for Serum Proteins (RPSP II). Analytical recoveries of the commercial calibrators varied. Also, assigned protein concentrations in both the WHO and RPSP II preparations made them unacceptable to us as benchmark calibrators for the Behring Nephelometer. Individual proteins (IgG, IgA, IgM, and transferrin) were obtained and primary standards prepared. Both transferrin and IgG were successfully standardized. However, IgA and IgM primary standards lacked 100% antigenicity, requiring removal of nonreactive IgA and IgM or reassignment of the correct value. The problem remains to find appropriate purified materials for IgA and IgM standardization.

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We assessed the Hitachi 736-30 as a possible replacement for the SMAC I and as a laboratory cost-saving measure. For 24 analytes, both intra- and interassay precisions were acceptable; they also had good measuring ranges. Essentially no interference from lipemia was observed, while minimal interference from bilirubin was demonstrated. Hemoglobin interfered in the measurement of 12 of the analytes. Correlation with the SMAC I, Demand, Astra-8, ACA, and Varian Atomic Absorption Spectrophotometer was found to be acceptable, except for chloride which showed poor correlation with SMAC I and Astra-8 (Hitachi = 0.888 [SMAC] + 11.102, r = 0.9652; Hitachi = 0.885 [Astra] + 10.264, r = 0.9136). The Hitachi 736-30 offers reagent and method flexibility, high volume capability, and "walk-away" operation.