[Renaliste] Calcémie corrigée

[A. Zannier, MD, MSc]

Chers amis,
Un article sur le sujet vient d'être mis en ligne par NDT (Cf. infra).
Amicalement,

A. Zannier, MD, MSc

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Goransson LG, Skadberg O, Bergrem H. Albumin-corrected or ionized calcium in 
renal failure? What to measure? Nephrol Dial Transplant. 2005 Jul 19; [Epub 
ahead of print]

BACKGROUND: Secondary hyperparathyroidsm is frequently observed in patients 
with chronic renal failure, and clinical treatment guidelines have been 
published. Despite this, a large proportion of patients do not reach the 
target levels for calcium, phosphorus, calcium x phosphorus product, or 
intact parathyroid hormone. The use of albumin-corrected calcium is 
recommended as calcium measurement, but it is the concentration of ionized 
calcium that is biologically active. We hypothesized that in clinical 
practice, the use of ionized calcium rather than albumin-corrected calcium 
would influence the calcium classification of the individual patient. 
METHODS: Blood samples from 34 patients in chronic haemodialysis were 
analysed for evaluation of mineral metabolism according to K/DOQI 
guidelines. Blood for analysis of total and ionized calcium was drawn 
simultaneously. As ionized calcium is pH dependent, samples were analysed at 
the actual pH of the individual patient. RESULTS: For both methods, a 
similar number of patients were characterized as normocalcaemic. The use of 
albumin-corrected calcium caused one patient (3%) to be classified as 
hypocalcaemic, and 10 patients (26%) as hypercalcaemic whereas with ionized 
calcium, five (15%) and three patients (9%) were classified as hypo- and 
hypercalcaemic, respectively. CONCLUSIONS: According to present guidelines, 
the difference in calcium classification of patients might have clinical 
implications for the prescription of vitamin D, and on the choice of 
phosphate binders.