Clarilab

Kidney and electrolytes

BUN test

Also called blood urea nitrogen

The nitrogen part of urea (urea ≈ BUN × 2.14).

Typical range
7–21 mg/dL.
Usual recheck
About 3 months when out of range

Why it's done

Part of the KFT in some labs.

What a high result can mean

Same causes as high urea.

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More kidney and electrolytes tests

Kidney function test (KFT)Creatinine, urea or BUN, uric acid, eGFR and usually electrolytes. CreatinineA waste product from muscles, cleared by the kidneys. eGFRAn estimate of how much blood your kidneys filter each minute, worked out from… UreaA waste product from protein breakdown, cleared by the kidneys. Uric acidA waste product from purines in food and cells. Urine albumin (UACR)Small amounts of protein (albumin) leaking into urine.