臨床の場におけるCa濃度評価に適したAlb補正Ca式の検討 —Caイオン化率[ガス分析イオン化Ca（iCa）/生イ匕学血清Ca]から 導いた新しいAlb補正Ca式の提案一

摘要

We calculated the Ca ionization rate (CaIR) that is the pH-corrected iCa (pH-iCa) measured by gas analysis divided serum total Ca (tCa) measured by biochemical assay. Alb-corrected Ca by CaIR (CalR-Ca) was determined by dividing the product of tCa and CaIR at measured Alb value by CaIR at Alb 4.0 g/dL. In 840 samples from 362 men, the relationship between CaIR and Alb was y = 0.623x - 0131(R2 = 0.455), and the relationship between CalR-Ca and pH-iCa was y = 6.934x + 0.894 (R2 = 0.824). The iCa corresponding to Ca 8.4 to 10.0 mg/dL were 1.09 to 1.33 mmol/L. CalR-Ca is more corresponded to pH-iCa than conventional Alb-corrected Ca or tCa without Alb correction. It reduced the frequency of hidden hypocalcemia, pseudo-hypocalcemia, and pseudo-hypercalcemia comparing with Payne or modified Payne formula and tCa without Alb correction, CalR-Ca is useful for the evaluation of Ca concentration in the clinical setting and may be preferable to iCa. [Original]