Ionized calcium in patients with chronic renal failure

Parameters of various renal disorders were studied in 31 patients (17 men and 14 women) who all were in the stage of chronic renal failure (CRF). These parameters included total serum creatinine, ionized calcium, serum creatinine, creatinine clearance and acid-base balance. The results were compared with a control group of 30 healthy subjects. In the patients with first stage CRF, the total serum calcium did not significantly decrease (mean = 2.19 +/- 0.12 mmol/l) and ionized calcium was within reference value limits (mean = 1.28 +/- 0.02 mmol/l). The percentage of ionized calcium in total serum calcium was higher for these patients (mean = 58.43%) than for the control group (mean = 52.25%). For patients with first and second stage CRF, the total serum was significantly lower (mean = 1.92 +/- 0.03 mmol/l) than for the healthy controls (p < 0.001) as well as for patients with first stage CRF (p < 0.05). The ionized calcium in these patients was not significantly lower (mean = 1.14 +/- 0.01 mmol/l); however, its percentage was higher than that of serum calcium (mean = 59.38%). There was a slight negative correlation between the levels of ionized calcium and serum creatinine in patients with first stage CRF (r = -0.30) and a significant correlation in patients with second and third stage CRF.