Anion Gap Calculator
Calculate anion gap to assess acid-base disorders
Table of Contents
How to Use
- Enter sodium (Na+) level in mEq/L
- Enter chloride (Cl-) level in mEq/L
- Enter bicarbonate (HCO3-) level in mEq/L
- Click calculate to see the anion gap result
What is Anion Gap?
The anion gap is a calculated value derived from electrolyte levels in the blood. It represents the difference between measured cations (positively charged ions) and anions (negatively charged ions) in serum.
The formula is: Anion Gap = Na+ - (Cl- + HCO3-). A normal anion gap is typically between 3-11 mEq/L.
Clinical Significance
The anion gap helps identify the cause of metabolic acidosis:
- Normal anion gap (3-11 mEq/L): Indicates normal electrolyte balance
- High anion gap (>11 mEq/L): May indicate diabetic ketoacidosis, lactic acidosis, renal failure, or toxin ingestion
- Low anion gap (<3 mEq/L): Rare, may indicate hypoalbuminemia or multiple myeloma
When to Calculate Anion Gap
Anion gap calculation is useful in:
- Evaluation of metabolic acidosis
- Assessment of acid-base disorders
- Monitoring patients with diabetes or renal disease
- Investigation of unexplained symptoms like confusion or rapid breathing
- Quality control of laboratory electrolyte measurements
Frequently Asked Questions
- What is a normal anion gap value?
- A normal anion gap typically ranges from 3 to 11 mEq/L. However, normal ranges may vary slightly between laboratories.
- What causes a high anion gap?
- High anion gap metabolic acidosis can be caused by diabetic ketoacidosis, lactic acidosis, renal failure, toxin ingestion (methanol, ethylene glycol), or salicylate poisoning.
- Is anion gap affected by albumin levels?
- Yes, albumin is a negatively charged protein that affects the anion gap. Low albumin levels can lead to a falsely low anion gap, and some clinicians use an albumin-corrected anion gap formula.
- Can I use this calculator instead of seeing a doctor?
- No, this calculator is for educational purposes only. Always consult with a healthcare provider for proper interpretation of laboratory results and medical advice.
Related Calculators
health
Ankle-Brachial Index (ABI) Calculator
health
Blood Alcohol Content (BAC) Calculator