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Serum/plasma mass concentration of substance (e.g., a specific biomarker or protein)

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

This test measures the amount of a particular substance in your blood, typically used to assess health conditions or monitor treatment effects.

Quick summary

["This test helps doctors understand levels of important substances in your blood."]

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

Key facts at a glance

LOINC
70103-7
Short code
MTX sp6 SerPl-sCnc
Synonyms
MTX sp6 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

What This Test Measures

The test detects the mass concentration of a specific substance in your serum or plasma. This could include proteins, hormones, or other biomarkers depending on the clinical need. The method used may involve advanced techniques like immunoassay or chromatography to ensure accuracy.

Why It’s Ordered

Doctors may order this test to diagnose or monitor conditions such as infections, metabolic disorders, or responses to medications. It can also help track progress in treatments like chemotherapy or hormone therapy.

Common Uses

This test is often used in research, specialized diagnostics, or when standard lab tests are insufficient to identify specific health issues. It may be particularly useful for detecting rare biomarkers or substances not typically measured in routine blood work.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum (liquid part after clotting) or plasma (liquid part after anticoagulant use). The sample is sent to a lab for specialized analysis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

What does this test tell me about my health?
The results help healthcare providers identify elevated or low levels of specific substances that may indicate conditions like genetic disorders, infections, or drug interactions. For example, it could reveal abnormal protein levels or biomarkers tied to diseases like cancer or autoimmune disorders.
How long will I need to wait for results?
Results may take several days to a week, depending on the lab’s workload and complexity of the test. Your doctor will contact you once they are ready to discuss the findings.
Can I eat or drink before this test?
For most blood-based tests like this one, you can eat and drink normally unless your doctor specifies otherwise. However, follow any fasting instructions they provide for your specific test.
  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