1. What is the Adjusted Calcium Calculation?

The adjusted calcium calculation corrects total calcium levels based on albumin concentration. Since approximately 50% of calcium is bound to albumin in blood, low albumin levels can lead to falsely low total calcium measurements.

2. How Does the Calculator Work?

The calculator uses the standard adjustment formula:

Where:

• \( \text{Ca} \) — Measured total calcium (mg/dL)
• \( \text{Albumin} \) — Serum albumin concentration (g/dL)
• 4 — Standard albumin reference value (g/dL)
• 0.8 — Correction factor (mg/dL calcium per g/dL albumin)

Explanation: The formula adjusts calcium levels to what they would be if albumin were at the normal value of 4 g/dL.

3. Importance of Adjusted Calcium

Details: Corrected calcium provides a more accurate assessment of calcium status in patients with abnormal albumin levels, which is crucial for diagnosing and managing calcium disorders, particularly in critically ill, malnourished, or liver disease patients.

4. Using the Calculator

Tips: Enter measured total calcium in mg/dL and serum albumin in g/dL. Both values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: When should calcium be adjusted for albumin?
A: Always adjust calcium levels when albumin is abnormal, particularly in hospitalized patients, those with malnutrition, liver disease, or nephrotic syndrome.

Q2: What are normal calcium values?
A: Normal total calcium is typically 8.5-10.5 mg/dL. Normal adjusted calcium should fall within this same range.

Q3: Are there different correction formulas?
A: Yes, some institutions use different correction factors (typically 0.8-1.0 mg/dL calcium per g/dL albumin). This calculator uses the most widely accepted 0.8 factor.

Q4: Does this adjustment work for ionized calcium?
A: No, ionized calcium (the physiologically active form) does not need albumin adjustment. This formula is only for total calcium correction.

Q5: What clinical conditions affect calcium-albumin binding?
A: Acid-base status affects binding - acidosis decreases binding (increasing ionized calcium), while alkalosis increases binding (decreasing ionized calcium).