Collaborative study for the establishment of the human immunoglobulin for electrophoresis Ph. Eur. BRP batch 3.

Due to the diminished stocks of the 2(nd) batch of the European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for human immunoglobulin for electrophoresis, in 2013, the European Directorate for the Quality of Medicines and HealthCare (EDQM) initiated an international collaborative study for the establishment of a replacement batch. The study was run under the aegis of the Biological Standardisation Programme (BSP). Seventeen laboratories participated in the collaborative study to verify the suitability of the candidate reference preparation according to the Ph. Eur. monographs 0338 and 0918 using the zone electrophoresis (ZE) method with either cellulose acetate and/or agarose as the testing medium. The candidate preparation was found suitable for the intended purpose and was subsequently adopted by the Ph. Eur. Commission as the human immunoglobulin for electrophoresis BRP batch 3 with an assigned range for immunoglobulin of 79.8 % to 86.4 % of the total protein content.

Interpretation of capillary zone electrophoresis compared with cellulose acetate and agarose gel electrophoresis: reference intervals and diagnostic efficiency in dogs and cats.

BACKGROUND: Serum protein electrophoresis is widely used for diagnostic and research purposes. Cellulose acetate (CAE) and agarose gel (AGE) electrophoresis are the most frequently used methods, but capillary zone electrophoresis (CZE) is beginning to be used more in veterinary laboratories. However, reference intervals for CZE in animals and comparison studies with the other electrophoretic techniques are lacking, compromising the diagnostic utility of CZE. OBJECTIVES: The aims of this study were to compare results obtained using CAE, AGE, and CZE; to establish reference intervals for CZE in dogs and cats; and to assess the capacity of CZE to detect abnormalities identified by AGE. METHODS: Serum samples from 204 dogs, including 104 healthy animals, and 62 cats, including 28 healthy animals, were analyzed using automated systems for CAE, AGE, and CZE. Descriptive statistics and Passing-Bablok and Bland-Altman tests were used to compare results. For each technique, reference intervals were calculated based on results from healthy animals. Concordance between CZE and AGE in detecting pathologic changes was assessed using Cohen's k coefficient. RESULTS: For most protein fractions, values obtained by CAE, AGE, and CZE were significantly different from each other, and constant and proportional errors were often detected. Nevertheless, reference intervals obtained by the 3 techniques overlapped. Moreover, Cohen's k coefficient demonstrated that the capacity of CZE and AGE to detect pathologic changes was comparable. CONCLUSIONS: CZE performs comparably to AGE and CAE as long as CZE-specific reference intervals are used for interpretation and distinctive visual patterns for albumin, gaps between fractions, and subpeaks found on CZE tracings are recognized. In addition, CZE offers several technical advantages, such as ease of use and complete automation.

Determinación de CK-MB: interferencias en la utilización del método inmunológico / Determination of CK-MB: interferences in the use of an immunological method

En la práctica diaria, cuando se realiza la determinación de creatinquinasa isoenzima MB (CK-MB) por el método inmunológico, es habitual obtener resultados incongruentes: valores de CK-MB cercanos o superiores al de creatinquinasa total (CK). En el presente trabajo se informa acerca de las interferencias más frecuentes encontradas con este método en nuestro Instituto (AU)

Determinación de CK-MB: interferencias en la utilización del método inmunológico / Determination of CK-MB: interferences in the use of an immunological method

En la práctica diaria, cuando se realiza la determinación de creatinquinasa isoenzima MB (CK-MB) por el método inmunológico, es habitual obtener resultados incongruentes: valores de CK-MB cercanos o superiores al de creatinquinasa total (CK). En el presente trabajo se informa acerca de las interferencias más frecuentes encontradas con este método en nuestro Instituto

Analysis of serum urinary proteins in normal and renal diseases by cellulose acetate electrophoresis.

A method using dried polyacrylamide gel to concentrate urine samples has been described, tested and used for the purpose of urine protein analysis. Concentrated urine samples from 10 normals and 100 patients with IgM nephropathy and systemic lupus erythematosus (SLE) were analysed by cellulose acetate electrophoresis (CAE). The results demonstrated that the patterns of proteins in the electrophoresis could be used to discriminate the two diseases. The best discriminating power was found in the logarithm of gamma globulin to albumin ratio. In IgM nephropathy the ratio of gamma globulin to albumin is much smaller than the ratio in SLE, indicating that relatively larger gamma globulins were excreted in SLE. In addition, the ratio can be used to discriminate subgroups of patients with IgM nephropathy. Urine from patients with IgM nephropathy with focal and segmental changes showed a significantly higher ratio. The study indicated the usefulness of the technique in discriminating the two common glomerular diseases.

Immunochemical LD1 assay for myocardial infarction.

The diagnostic efficiency of an immunochemical assay for LD1 (I-LD1) was compared with an electrophoretic procedure for this isoenzyme (E-LD1) in 100 consecutive patients hospitalized for a clinical suspicion of acute myocardial infarction (MI). All patients were investigated with a standard protocol including serial determinations of total creatine kinase (CK) and lactic dehydrogenase (LD) activities, CK and LD isoenzymes, and electrocardiograms. Thirty-two patients were diagnosed to have acute MI on the bases of positive CK-MB or EKG or both. The coefficients of variation for the intraassay and interassay precision of I-LD1 assay ranged from 3.12% to 7.69%. Direct correlation between the I-LD1 and E-LD1 was very satisfactory (r = .961; P = less than .001). When the results of these two procedures were compared in terms of decision values for acute MI, there was agreement between them in 87 patients. At the cut-off point of 90 U/L, I-LD1 assay was 100% sensitive and 89% specific for acute MI; the corresponding figures for E-LD1 were 81% and 91%, respectively. The diagnostic efficiencies of the I-LD1 and E-LD1 procedures were 93% and 88%, respectively. A substantial saving in technologist time with the I-LD1 assay over the E-LD1 procedure was documented in this study.