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Serum or Plasma Substance Concentration (Mass Concentration) for a Specific Protein or Metabolite (e.g., Cystatin C)

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

This test measures the amount of a specific substance (like a protein or metabolite) in your blood, usually taken from serum or plasma.

Quick summary

["Helps assess kidney function or other metabolic processes depending on the analyte."]

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

Key facts at a glance

LOINC
70102-9
Short code
MTX sp5 SerPl-sCnc
Synonyms
MTX sp5 SerPl-sCnc
Category
chemistry
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 Is Done

Doctors may order this test to monitor kidney health, detect metabolic disorders, or evaluate other conditions affecting blood chemistry. The exact reason depends on your symptoms or medical history.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours if your test involves blood drawn after an overnight fast. Wear a comfortable shirt for easy access.

What Happens During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to a standard range for that specific substance. Abnormal levels may indicate conditions like kidney disease, genetic disorders, or other metabolic issues. Your doctor will discuss these results with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum/plasma mass concentration test

Frequently asked questions

What does this test measure?
This test measures the concentration of a specific substance (like a protein or metabolite) in your blood, often used to assess kidney function, metabolic health, or other systemic conditions.
Some tests may require fasting for a few hours, but others do not. Your healthcare provider will give specific instructions based on your test type.
Check with your doctor or lab technician about whether to stop taking certain medications before the test, as some may affect results.
You may feel a slight pinch when the blood is drawn, but most people describe it as minimal discomfort. The process usually takes a few minutes.
Your doctor will review your results with you and explain what they mean in the context of your health. Further testing or treatment may be recommended if needed.
  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