BUN/Creatinine Ratio with eGFR [296X]

2968

Urea Nitrogen (BUN), Creatinine, eGFR, BUN/Creatinine Ratio (calculated)

2 mL serum collected in a serum separator tube (SST)

1 mL

Spun SST

Room temperature

Room temperature: 7 days
Refrigerated: 5 days
Frozen: 28 days

Set up: Daily; Report available: 1-2 days

eGFR is intended for patients with stable renal function.

⁠⁠⁠⁠⁠⁠⁠Urea Nitrogen (BUN)

Age	Male    (mg/dL)	Female    (mg/dL)
<1 Month	4-12	3-17
1-11 Months	2-13	4-14
1-3 Years	3-12	3-14
4-19 Years	7-20	7-20
≥20 Years	7-25	7-25

Creatinine

Age	Male    (mg/dL)	Female    (mg/dL)
≤2 days	0.79-1.58	0.79-1.58
3-27 days	0.35-1.23	0.35-1.23
1 month-9 years	0.20-0.73	0.20-0.73
10-12 years	0.30-0.78	0.30-0.78
13-15 years	0.40-1.05	0.40-1.00
16-17 years	0.60-1.20	0.50-1.00
18-29 years	0.60-1.24	0.50-0.96
30-39 years	0.60-1.26	0.50-0.97
40-49 years	0.60-1.29	0.50-0.99
50-59 years	0.70-1.30	0.50-1.03
60-69 years	0.70-1.35	0.50-1.05
70-79 years	0.70-1.28	0.60-1.00
≥80 years	0.70-1.22	0.60-0.95

For patients >49 years of age, the upper reference limit for creatinine is approximately 13% higher for people identified as African-American.

eGFR	≥60 mL/min/1.73m2

Bun/Creatinine Ratio

<1 year	Not Established
1-5 years	16-50	calc
6-10 years	13-36	calc
11-16 years	9-25	calc
≥17 years	6-22	calc

The BUN/Creatinine ratio is useful in the differential diagnosis of acute or chronic renal disease. Reduced renal perfusion, e.g., congestive heart failure, or recent onset of urinary tract obstruction will result in an increase in BUN/Creatinine ratio. Increased urea formation also results in an increase in the ratio, e.g., gastrointestinal bleeding, trauma, etc. When there is decreased formation of urea as seen in liver disease, there is a decrease in the BUN/Creatinine ratio. In most cases of chronic renal disease the ratio remains relatively normal.