Using the data: Na+ 143 mmol/L; K+ 4.9 mmol/L; Cl- 105 mmol/L; HCO3- 25 mmol/L, which statement is false?

Using the data: Na+ 143 mmol/L; K+ 4.9 mmol/L; Cl- 105 mmol/L; HCO3- 25 mmol/L, which statement is false?

• A. Patient results are not acceptable.
• B. Anion gap is useful in detecting some disease states.
• C. Anion gap equals 18 mmol/L.
• D. Anion gap is useful for checking analytical error.

Answer: (A)

Anion gap is a quick check for unmeasured anions in the blood and helps us detect certain metabolic disturbances or lab issues. It can be calculated with or without including potassium. Using the standard formula without potassium: 143 − (105 + 25) = 13 mmol/L. This value is within the common reference range, so the results are acceptable. If potassium is included, (143 + 4.9) − (105 + 25) ≈ 17.9, about 18 mmol/L. This also falls within the expanded reference range labs use when including potassium. Because the computed gap is normal in either approach, the statement claiming the patient results are not acceptable is false. The other points—an ion gap helping detect disease states, being around 18 mmol/L when using the potassium-included calculation, and serving as a check for analytical error—are all reasonable and true uses of the anion gap.

Anion gap is a quick check for unmeasured anions in the blood and helps us detect certain metabolic disturbances or lab issues. It can be calculated with or without including potassium.

Using the standard formula without potassium: 143 − (105 + 25) = 13 mmol/L. This value is within the common reference range, so the results are acceptable.

If potassium is included, (143 + 4.9) − (105 + 25) ≈ 17.9, about 18 mmol/L. This also falls within the expanded reference range labs use when including potassium.

Because the computed gap is normal in either approach, the statement claiming the patient results are not acceptable is false. The other points—an ion gap helping detect disease states, being around 18 mmol/L when using the potassium-included calculation, and serving as a check for analytical error—are all reasonable and true uses of the anion gap.