Serum or Plasma Substance Concentration (General Protein or Peptide, e.g., Neurotrophic Factor)
This test measures the level of a specific protein or peptide in your blood, often related to mood, brain function, or overall health. It may help assess conditions like depression, neurological disorders, or metabolic balance.
["This test helps doctors understand how certain proteins in your blood may affect your mood or health."]
Key facts at a glance
- LOINC
- 28163-4
- Short code
- NOTENJOYINGLIFE
- Synonyms
- —
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- reported-living-hiv
- 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 healthcare provider may recommend this test if they suspect a condition affecting mood, brain chemistry, or metabolic processes. It could be part of an evaluation for depression, anxiety, neurological disorders, or other health concerns linked to specific proteins in the blood.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours if the test involves a specific protein related to digestion or metabolism. Bring any medications you’re currently taking to your appointment.
During the Test
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
Results will show the concentration of the protein or peptide in your blood. While reference ranges vary depending on the specific protein tested, abnormal levels may indicate potential health concerns that need further evaluation by your doctor.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal levels of this protein or peptide may suggest underlying conditions such as hormonal imbalances, neurological disorders, or metabolic issues. For example, certain proteins are linked to mood regulation, while others may indicate inflammation, nutrient deficiencies, or other systemic health problems. Your doctor will interpret results in the context of your overall health and symptoms.
Frequently asked questions
What does a high or low level of this protein mean?
How often will I need this test?
Can I eat or drink before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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