RESUMO
Analyzing 415 measurements from 33 patients on chronic maintenance hemodialysis we confirm that 50% of total calcium in the range 1.59 to 3.33 mmol/l gives a valuable approximation to ionized calcium in the range 0.79 to 1.62 mmol/l. However, a small but significant effect of albumin and phosphate on ionized calcium can also be demonstrated. Conventional albumin correction of total calcium using the formula: total calcium + (43 g/l-Albumin g/l).0.017 mmol/g is of poor value in these patients on maintenance hemodialysis.
Assuntos
Cálcio/sangue , Falência Renal Crônica/sangue , Diálise Renal , Humanos , Hipercalcemia/diagnóstico , Hipocalcemia/diagnóstico , Falência Renal Crônica/terapia , Pessoa de Meia-Idade , Fosfatos/sangue , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Albumina Sérica/análiseRESUMO
To study how much the serum phosphate concentration could vary on the day before scheduled dialysis we obtained 24-37 timed measurements during 24 h in nine patients on maintenance haemodialysis. During the observation there was an increase in serum phosphate concentration of 0.239 +/- 0.022, P < 0.01). Surprisingly six of the nine patients exhibited nine statistically and clinically significant nadirs with decrements of 0.21 +/- 0.04 mmol/l against an intra-assay standard deviation of about 0.05 mmol/l. Five of the nadirs occurred at 11.40-14.50, mean 12.59, and three at 19.00-21.30, mean 20.00. We found no coinciding changes in the serum calcium concentration. These findings indicate that serum phosphate concentrations do not always reflect phosphorus balance or intake.
