Urea by age and sex

What’s typical for urea at every adult age, from a U.S. government health survey of 19,127 people, next to the usual ranges labs print.

NHANES 2015–2016, 2017–March 2020 (pre-pandemic), August 2021–August 202319,127 adultsAI-verified against cited sources. Awaiting expert review

What’s typical at one age

Pick a sex and an age to see the spread among U.S. adults like that, and type a result to see where it falls.

Age: 45

U.S. women aged 40–49

1,529 people in NHANES, 2015–2016, 2017–March 2020 (pre-pandemic), August 2021–August 2023.

Median (half are lower): 26 mg/dL
Middle half of people: 21 to 31
Middle 90% of people: 15 to 40
Usual range a lab prints: 15 to 42

Shaded: the middle 90% and middle half of people. Dark line: the median. The bracket above: the usual range.

Your result (optional, in mg/dL)

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Across adult life

NHANES describes the US civilian, non-institutionalized population, not a 'healthy' reference group. People with disease, on medication, fasting or not (except fasting-subsample markers), smokers and so on are all included. A percentile says where a value sits among Americans of that sex and age, not whether it is normal.

How Urea varies with age in the U.S.Shaded: middle 90% and middle 50% of people. Line: the median. mg/dL. Point at any age, or focus the chart and use the arrow keys, to read both sexes in words.

Reference data derived from CDC/NCHS National Health and Nutrition Examination Survey (NHANES), cycles 2015-2016, 2017-March 2020 (pre-pandemic), August 2021-August 2023. Analysis by bloodtesttracker.com; not endorsed by CDC, NCHS or HHS.

Every percentile

Download this table (CSV)

The 25th percentile means a quarter of people in that group had a lower result. In mg/dL. A dash means too few people were measured for the survey to publish that number.

Women

Urea percentiles for U.S. women by age, in mg/dL, NHANES 2015–2016, 2017–March 2020 (pre-pandemic), August 2021–August 2023
Age	People	2.5th	5th	10th	25th	Median	75th	90th	95th	97.5th
18–29	1,682	12	14	15	19	23	28	32	36	39
30–39	1,514	13	15	17	20	24	29	34	38	41
40–49	1,529	13	15	17	21	26	31	36	40	44
50–59	1,635	15	17	19	24	28	35	41	45	49
60–69	1,919	18	19	21	27	32	39	47	54	62
70–79	1,082	18	20	23	28	35	43	53	60	67
80+	585	21	24	27	32	40	50	63	71	76
All adults	9,946	14	15	18	22	27	34	43	48	56

Men

Urea percentiles for U.S. men by age, in mg/dL, NHANES 2015–2016, 2017–March 2020 (pre-pandemic), August 2021–August 2023
Age	People	2.5th	5th	10th	25th	Median	75th	90th	95th	97.5th
18–29	1,640	15	17	19	23	27	33	40	43	45
30–39	1,308	15	17	19	24	28	33	39	43	46
40–49	1,311	17	19	21	26	31	36	42	45	50
50–59	1,427	17	19	21	26	31	38	46	51	54
60–69	1,803	18	21	24	29	34	41	47	53	59
70–79	1,129	19	22	25	30	37	45	54	63	71
80+	563	22	25	27	33	42	54	69	81	96
All adults	9,181	16	19	21	25	31	38	45	51	57

About these numbers

NHANES describes the US civilian, non-institutionalized population, not a 'healthy' reference group. People with disease, on medication, fasting or not (except fasting-subsample markers), smokers and so on are all included. A percentile says where a value sits among Americans of that sex and age, not whether it is normal.
Assays differ between labs and between NHANES cycles. Values from a commercial lab can sit a few percent higher or lower than NHANES for the same blood. Earlier cycles were bridged to the 2021-2023 method with NCHS equations where NCHS recommends it.
Age 80 and over is top-coded at 80 in public NHANES files, so the 80+ cell mixes everyone 80 and older.
2021-2023 (cycle L) had a 25.7% exam response rate and no race/income oversampling; NCHS advises caution when combining it with earlier cycles.
BUN (mg/dL) x 0.357 = urea (mmol/L), the NHANES SI conversion (LBDSBUSI).

Centers for Disease Control and Prevention (CDC). National Center for Health Statistics (NCHS). National Health and Nutrition Examination Survey Data. Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2015-2016, 2017-March 2020 (pre-pandemic), August 2021-August 2023. https://wwwn.cdc.gov/nchs/nhanes/

How we use survey data

The usual range at every age

The reference range labs print, for each age group. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

Usual range of Urea by age, in mg/dL
Who	Usual range
Women, 18–29	15–39 mg/dL
Women, 30–49	15–42 mg/dL
Women, 50–59	18–48 mg/dL
Women, 60–69	18–51 mg/dL
Women, 70–79	21–57 mg/dL
Women, 80–89	21–60 mg/dL
Women, 90+	24–60 mg/dL
Men, 18–29	18–45 mg/dL
Men, 30–49	18–48 mg/dL
Men, 50–59	21–51 mg/dL
Men, 60–69	21–54 mg/dL
Men, 70–79	21–57 mg/dL
Men, 80–89	24–60 mg/dL
Men, 90+	27–60 mg/dL
0.077–0	6–33 mg/dL
1–15	15–39 mg/dL
16+	15–47 mg/dL

Sources: Sonic Healthcare Australia, North West London Pathology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Association for Clinical Biochemistry and Laboratory Medicine (author W. Marshall), Oxford University Hospitals NHS Foundation Trust, DiaSys Diagnostic Systems GmbH, Fleury Medicina e Saúde