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Nitrogenous Waste Substance Concentration in Serum (e.g., Urea, Creatinine, or Other Metabolites)

Published: August 9, 2026Updated: August 16, 2026

This test measures certain waste products in your blood, which can help your doctor assess how well your kidneys are working or identify metabolic issues.

Quick summary

["Kidney function and metabolic health may be evaluated with this blood test."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
17647-9
Short code
S pneum Ab Ser-aCnc
Synonyms
S pneum Ab Ser-aCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like fatigue, swelling, frequent urination, or unexplained weight changes. It could also be part of routine check-ups or monitoring for conditions like kidney disease, diabetes, or liver problems.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw if your doctor specifies. Stay hydrated unless instructed otherwise.

What the Test Involves

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

Higher-than-normal levels of these waste products may signal kidney problems, fluid imbalance, or other metabolic disorders. Lower-than-normal levels might indicate dehydration or certain liver issues. Your doctor will interpret the results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Nitrogenous Waste Test

Frequently asked questions

What causes elevated nitrogenous waste levels?
Elevated levels can result from kidney problems (such as reduced kidney function), dehydration, heart failure, liver disease, or certain medications. It may also be linked to metabolic conditions like diabetes or severe infections.
What if my results are abnormal?
If your results are abnormal, your doctor will discuss them with you and may recommend additional tests, like kidney function tests (e.g., creatinine clearance) or imaging studies. They may also adjust your treatment plan if needed, such as modifying medications or improving hydration.
Can I eat or drink before this test?
Generally, no special diet is required unless your doctor instructs otherwise. However, if your test involves fasting (e.g., for glucose-related nitrogenous substances), follow their guidance to ensure accurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy