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BUN/Creatinine, Post Dialysis

Dialysis BUN/Creatinine, Blood Urea Nitrogen/Creatinine

Test Codes

Beaker: PBCR2

Department

Chemistry

Instructions

This test is only available to Dialysis patients.

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)
Contact the Laboratory for the acceptability of other tube types. 

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

• Moderate to grossly hemolyzed specimens.
• Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes and Microtainers^® to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 

Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day.
Results available within 4 hours.

Reference Range

Urea (BUN):

Age	Male (mg/dL)	Female (mg/dL)
0-14 days	3	23
15 days - <1 year	3	17
1-10 years	9	22
10-18 years	7	21
19-adult	7	25

Creatinine (Male):

Male - Age	mg/dL	mg/dL
0 - 14 days	0.42	1.05
15 days - <1 year	0.32	0.53
1 - 3 years	0.38	0.54
4 - 6 years	0.44	0.64
7 - 11 years	0.52	0.69
12 - 14 years	0.57	0.8
15 - 16 years	0.66	1.04
17 - 18 years	0.69	1.1
19 - adult	0.60	1.30

Creatinine (Female):

Female - Age	mg/dL	mg/dL
0 - 14 days	0.42	1.05
15 days - <1 year	0.32	0.53
1 - 3 years	0.38	0.54
4 - 6 years	0.44	0.64
7 - 11 years	0.52	0.69
12 - 14 years	0.57	0.8
15 - 16 years	0.59	0.86
17 - 18 years	0.6	0.88
19 - adult	0.50	1.10

Test Methodology

Enzymatic Urease, Spectrophotometry, or Conductivity Electrode.

Interpretation

BUN results will be used for two calculations:

1. Kt/V (A dialysis dose calculation using patient's post dialysis weight, volume of ultrafiltrate (L), and BUN results.)
2. %URR (Urea Reduction Ratio) = 100*((pre-BUN - post-BUN)/pre-BUN)

Clinical Utility

This test is used to assess the adequacy of dialysis.

CPT Codes

84520, 82565.

Contacts

Last Updated

9/25/2023