Blood Urea Nitrogen

Also called BUN

What it measures

BUN and urea describe the same underlying waste product but are scaled by different conventions — BUN counts only the nitrogen atoms in the molecule, urea counts the whole thing — so a BUN value and a urea value are not interchangeable without converting first, and the two are kept as separate tests here for exactly that reason. mg/dL is the standard convention for BUN.

Reading it in a different unit

This lab reports Blood Urea Nitrogen in mg/dl. Reports from other labs — especially ones using European or US-style formatting — sometimes use a different unit for the same measurement. The relationship between them:

Unit conversions verified against published molar masses and LOINC definitions. This is not a diagnostic reference — the normal range for any test is set by the laboratory that ran it and printed on your report.

Why this matters for tracking a trend

A value plotted next to earlier results only tells you something if every point is on the same scale. Two readings of the same test from two different labs, in two different units, can look like a dramatic change when nothing about your actual result changed — only the unit did. Converting to one scale before comparing is what keeps a trend line honest.

LOINC codes for this test: 3094-0, 6299-2.

General information about laboratory measurement, not medical advice. Whether a specific result is normal for you depends on your lab's reference range, your history and your doctor's judgement — not on this page.