KidneyReported in mg/dLBlood urea nitrogen (BUN)
Nitrogen from urea, the waste left after the body breaks down protein. Kidneys clear it. Diet and hydration move it.
What it measures
The liver turns ammonia from protein breakdown into urea. Blood urea nitrogen is the nitrogen portion of that urea. Kidneys excrete it. Unlike creatinine, BUN rises and falls with how much protein you eat and with whether you are dry. A high BUN with a normal creatinine is often dehydration or a high-protein load, not failed kidneys.
Why it is on the panel
BUN is the context around creatinine. The pair separates “needs a glass of water and a repeat” from “the filter is down.” It also climbs in gastrointestinal bleeding, because digested blood is a protein load.
How to read it
Divide the story, not the numbers, into three patterns. BUN and creatinine both high: kidneys, blockage, or a serious volume loss. BUN high and creatinine typical: dehydration, high protein intake, or gut bleeding. BUN low: low protein intake, liver disease, or overhydration.
When it runs higher
Dehydration, a high-protein diet, kidney disease, urinary obstruction, heart failure, and bleeding in the gut raise BUN. Steroids and tetracyclines can nudge it up. Thirst and a high sodium support the dehydration story.
When it runs lower
Low protein intake, pregnancy, overhydration, and severe liver disease lower BUN. A low result in someone who is eating normally and feels well is usually unremarkable.
Same group
Other Kidney tests
How to use this page
This page explains what the measurement is for. It is educational. Your Healiam report includes the reference interval for your age and sex, and a clinician reads that result with your history, medicines, and the rest of the panel. Talk with a clinician before changing diet, supplements, or treatment because of a number on a report.
Urea nitrogen
Urea nitrogen is part of the full panel.
No referral or insurance required.
One preventive draw covers this measurement and the rest of the Healiam panel. CLIA-certified results come back in days.