Hypoalbuminemia Corrected Calcium Calculator

Determines the accurate Ca levels in patients with lower than normal albumin.

In the text below the tool there is more information about the formulas used and about the implications of hypoalbuminemia.

In hypoalbuminemia, calcium correction is required because the actual calcium levels tend to be higher than those obtained through laboratory testing.

This calculator corrects the Ca levels based on the difference between normal serum albumin (4 g/dL or 40 g/L) and laboratory tested albumin.

Depending on the measurement system used, there are two calcium correction formulas:

Corrected Calcium = Serum Calcium (mg/dL) + 0.8 x (Normal albuminemia (g/dL) – Patient albuminemia (g/dL))

Corrected Calcium = Serum Calcium (mmol/L) + 0.02 x (Normal albuminemia (g/L) – Patient albuminemia (g/L))

Serum Calcium:*
Patient Albumin:*
Normal Albumin (g/dL):*
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Serum Calcium:*
Patient Albumin:*
Normal Albumin (g/L):*

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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.


Variables and formulas

The above calculator corrects calcium levels in patients with hypoalbuminemia. There are three fields to input, either in standard units (first tab) or SI units (second tab).

■ Serum calcium – in mg/dL or mmol/L;

■ Albumin (patient value) – in g/dL or g/L;

■ Normal albumin – set default at 4 g/dL or 40g/L.

The formula used is the following:

Corrected Calcium = Serum Calcium (mg/dL) + 0.8 x (Normal albuminemia (g/dL) – Patient albuminemia (g/dL))

Which can also be written like:

Corrected Calcium = Serum Calcium (mg/dL) + 0.8 x (4 g/dL – Patient albuminemia (g/dL))

If the SI units are used, the equations become:

Corrected Calcium = Serum Calcium (mmol/L) + 0.02 x (Normal albuminemia (g/L) – Patient albuminemia (g/L))

Corrected Calcium = Serum Calcium (mmol/L) + 0.02 x (40 g/L – Patient albuminemia (g/L))

Because albumin is the protein that binds calcium in the blood stream, the calcium level needs to be corrected if the albumin levels are higher (hyper-) or lower (hypo-) than normal. The reference range for albumin is between 3.5 and 5.5 g/dL (35 – 55 g/L).

The calcium correction helps determine the accurate Ca levels, as if albumin were in the normal range:

■ In hypoalbuminemia, corrected calcium (actual value) tends to be higher than tested calcium;

■ In hyperalbuminemia, corrected calcium tends to be lower than tested calcium.

Normal calcium levels vary between 8.5-10.5 mg/dL or 2.1-2.6 mmol/L depending on the testing laboratory.


Implications of hypoalbuminemia

Hypoalbuminemia is defined as low blood albumin levels (<3.5 g/dL). Albumin accounts for 50-60% of blood proteins and is involved in the transport of bilirubin, ions, hormones, fatty acids or exogenous substances, like medication.

If albumin levels are lower than normal, these substances remain free in the plasma and tend to go faster through the hepatic metabolism because of that.

Another role of blood proteins is that of sustaining the balance between osmotic and hydrostatic pressure and in preventing edema.

Low albumin levels can be caused by liver disease (especially cirrhosis), nephrotic syndrome, heart failure, burns, malnutrition etc.

Hypoalbuminemia can be found in many acute and chronic medical conditions and is a common indicator of the acute and chronic inflammatory response.


Original source

Payne RB, Little AJ, Williams RB, Milner Jr. Interpretation of Serum Calcium in Patients with Abnormal Serum Proteins. Br Med J. 1973; 4(5893): 643–646.

Other references

1. Parent X, Spielmann C, Hanser AM. Corrected calcium: calcium status underestimation in non-hypoalbuminemic patients and in hypercalcemic patients. Ann Biol Clin (Paris). 2009; 67(4):411-8.

2. Hall J. (2015) Guyton and Hall Textbook of Medical Physiology 13th ed. Elsevier Health Sciences.

Specialty: Deficiency

Objective: Correction

No. Of Variables: 3

Year Of Study: 1973

Article By: Denise Nedea

Published On: July 6, 2017 · 09:10 AM

Last Checked: July 6, 2017

Next Review: July 6, 2023