title: Influence of the assay for measuring serum albumin on corrected total calcium in chronic hemodialysis patients.
abstract: The Japanese Society for Dialysis Therapy guideline for secondary hyperparathyroidism recommends the use of albumin-corrected serum Ca as a therapeutic target in chronic hemodialysis patients; however, the assay used for albumin measurement may affect the corrected Ca level. In this study, we examined the impact of the albumin assay on corrected Ca levels in hemodialysis patients. We measured serum albumin using bromocresol green (BCG) and modified bromocresol purple (BCP) assays, and corrected Ca for albumin using Payne's formula in 422 hemodialysis patients (age 66±13 years; time on hemodialysis 116±111 months). Serum albumin values were 3.7±0.4 (1.4-4.6) g/dL by BCG and 3.3±0.4 (1.0-4.3) g/dL by modified BCP, with the differences between the two assays ranging from 0.0 to 0.6 with a mean of 0.35±0.09 g/dL. Serum C-reactive protein and globulin values were significantly higher in patients with differences in albumin greater than 0.5 g/dL (P<0.01). Based on the BCG method, 71 patients (16.8%) were classified with hypocalcemia, 51 (12.1%) with hypercalcemia, and 300 (70.0%) as normocalcemic. In contrast, when using modified BCP, 33 patients (7.9%) were labeled as hypocalcemic, while 92 (21.8%) were hypercalcemic. Depending on the use of either BCG or modified BCP, a discrepancy of classification was observed in 79 patients (18.7%): 41 patients were re-classified from normocalcemic to hypercalcemic, and 38 patients were re-classified from hypocalcemic to normocalcemic by selecting the modified BCP assay. These findings suggest that the type of assay used for albumin measurement has an impact on albumin-corrected Ca levels.
authors: Blood Purification Unit, Hamamatsu University School of Medicine Department of Nephrology, Maruyama Hospital, 1-20-1 Handayama, Higashi-ku, Hamamatsu-shi, Shizuoka, Japan. a.kato@hama-med.ac.jp
authors: Akihiko
authors: A
authors: Kato
authors: Takako
authors: T
authors: Takita
authors: Mitsuyoshi
authors: M
authors: Furuhashi
authors: Taiki
authors: T
authors: Fujimoto
authors: Hiroo
authors: H
authors: Suzuki
authors: Masahiro
authors: M
authors: Hakamada
authors: Yukitaka
authors: Y
authors: Maruyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001961:Bromcresol Green; D001962:Bromcresol Purple; D002097:C-Reactive Protein / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000175:diagnosis / Q000209:etiology; D006962:Hyperparathyroidism, Secondary / Q000209:etiology*; D006996:Hypocalcemia / Q000175:diagnosis / Q000209:etiology; D007202:Indicators and Reagents; D007564:Japan; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis*; D012955:Societies, Medical; D055815:Young Adult
chemical_list: D007202:Indicators and Reagents; D012709:Serum Albumin; D001962:Bromcresol Purple; D001961:Bromcresol Green; D002097:C-Reactive Protein; D002118:Calcium