Hypoalbuminemia: Calcium Correction
A normal serum calcium level is 8–10 mg/dL, which may vary slightly by laboratory. Hypercalcemia is a serum calcium level >10.5 mg/dL.
Hypercalcemia is classified as follows:
- Mild: Total Ca 10.5–11.9 mg/dL (2.5–3 mmol/L) or ionized Ca 5.6–8 mg/dL (1.4–2 mmol/L)
- Moderate: Total Ca 12–13.9 mg/dL (3–3.5 mmol/L) or ionized Ca 5.6–8 mg/dL (2–2.5 mmol/L)
- Hypercalcemic crisis: Total Ca 14–16 mg/dL (3.5–4 mmol/L) or ionized Ca 10–12 mg/dL (2.5–3 mmol/L)
Without correction, an abnormally high serum calcium level may appear normal.
Corrected Ca=([4˗plasma albumin in g/dL]×0.8+serum calcium)
|
If albumin is… |
Add this to calcium… |
If Albumin is… |
Add this to calcium… |
|
3.2 |
0.64 |
2.3 |
1.36 |
|
3.1 |
0.72 |
2.2 |
1.44 |
|
3.0 |
0.80 |
2.1 |
1.52 |
|
2.9 |
0.88 |
2.0 |
1.60 |
|
2.8 |
0.96 |
1.9 |
1.68 |
|
2.7 |
1.04 |
1.8 |
1.76 |
|
2.6 |
1.12 |
1.7 |
1.84 |
|
2.5 |
1.20 |
1.6 |
1.92 |
|
2.4 |
1.28 |
1.5 |
2.00 |
Note: Use ionized calcium levels in renal patients instead of correcting calcium levels for hypoalbuminemia whenever possible. In one study of 34 patients on chronic hemodialysis, the use of albumin-corrected calcium caused one patient (3%) to receive a classification as hypocalcemic and ten patients (26%) as hypercalcemic, whereas with ionized calcium, five (15%) and three patients (9%) were classified as hypocalcemic and hypercalcemic, respectively.
Ca=calcium, dL=deciliter, g=gram, L=liter, mg=milligram, mmol=millimole
Resources and recommended readings
Agraharkar A. Hypercalcemia.
Available at: http://emedicine.medscape.com/article/240681-overview.
Accessed May 10, 2011.
Goransson LG, Skadberg O, Bergrem H. Albumin-corrected or ionized calcium in renal failure? What to measure? Nephrol Dial Transplant [serial online]. 2005;20:2126-2129. Available at: http://ndt.oxfordjournals.org/content/20/10/2126.full.
Accessed May 10, 2011.
Review Date 7/11
G-1652
