Abstract
The levels of serum IgA and C3 in patients with IgA nephropathy were determined using international standard serum (IFCC/CRM470) in a multicenter trial in Japan. The ratio of serum IgA to C3 (serum IgA/C3 ratio) without any information from renal biopsy was used for the diagnosis of IgA nephropathy. Three hundred and six patients with IgA nephropathy and other glomerular diseases, and 418 healthy adults were examined. The new diagnostic standardized criterion in patients with IgA nephropathy, obtained by nephelometric immune assay based on the international reference preparation CRM470, was 315 mg/dl. The serum IgA/C3 ratio was a more useful marker for distinguishing IgA nephropathy from non‐IgA nephropathy together with serum IgA levels. This suggests that the measurement of serum IgA and C3 may predict the diagnosis of patients with IgA nephropathy prior to renal biopsy. J. Clin. Lab. Anal. 14:220–223, 2000. © 2000 Wiley‐Liss, Inc.
Keywords: serum IgA, serum IgA/C3 ratio, diagnosis, IgA nephropathy
REFERENCES
- 1. Berger J. 1969. IgA glomerular deposits in renal disease. Transplant Proc 1:939–944. [PubMed] [Google Scholar]
- 2. Tomino Y, Sakai H, Endoh M, Kaneshige H, Nomoto Y. 1982. Detection of immune complexes in polymorphonuclear leukocytes by double immunofluorescence in patints with IgA nephropathy. Clin Immunol Immunopathol 24:63–71. [DOI] [PubMed] [Google Scholar]
- 3. Whitworth JA, Leibowitz S, Kennedy JS, Cameron JS, Chantler C. 1976. IgA and glomerular disease. Clin Nephrol 5:33–36. [PubMed] [Google Scholar]
- 4. Harper SJ, Allen AC, Layward L, Hattersley J, Veitch PS, Feehally J. 1994. Increased immunoglobulin A and immunoglobulin A1 cells in bone marrow trephine biopsy specimens in immunoglobulin A nephropathy. Amer J Kidney Dis 24:888–892. [DOI] [PubMed] [Google Scholar]
- 5. Tomino Y, Sakai H, Miura M, et al. 1985. Discrepancy of serum IgA levels determined by single radial immunodiffusion and laser nephelometry in patients with IgA nephropathy. Am J Med Sci 290:56–60. [DOI] [PubMed] [Google Scholar]
- 6. Sakai H, Abe K, Kobayashi Y, et al. 1995. Clinical guidelines of IgA nephropathy. Jpn J Nephrol 37:417–421. [PubMed] [Google Scholar]
- 7. Itoh Y, Ichihara K, Kanno T, et al. 1997. Serum protein standardization project in Japan: evaluation of an IFCC reference material (RPPHS/CRM470) and establishment of reference intervals. J Clin Lab Analy 11:39–44. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Fink PC, Romer M, Haeckel R, Fateh‐Moghadam A, Delanghe J, Gressner AM, Dubs RW. 1989. Measurment of proteins with the Behring nephelometer. A multicenter evaluation. J Clin Chem Clin Biochem 27:261–276. [PubMed] [Google Scholar]
- 9. Zweig MH, Campbell G. 1993. Receiver‐operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine. Clin Chem 39:561–577. [PubMed] [Google Scholar]
- 10. Okumura N, Nomura M, Tada T, et al. 1990. Effects of sample storage on serum C3 assay by immunonephelometry. Clin Lab Sci 3:54–57. [Google Scholar]