Serum or plasma substance concentration (qualitative) for a specific protein or marker measured by immunoassay
This test detects the presence or absence of a particular substance in your blood, often used to identify certain proteins or markers that may indicate health conditions.
["This qualitative test helps determine if a specific substance is present in your bloodstream."]
Key facts at a glance
- LOINC
- 9975-4
- Short code
- QRS T-Amp L-AVR
- Synonyms
- QRS T-Amp L-AVR
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ekg
- 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
This test measures the concentration of a specific substance in your serum or plasma using an immunoassay method. Immunoassays detect and quantify substances like hormones, antibodies, or proteins by identifying their unique molecular structure. The result is qualitative, meaning it only tells you whether the substance is present or not, rather than providing an exact amount.
Why It Might Be Ordered
Your healthcare provider may order this test to screen for, confirm, or monitor conditions related to the presence of specific substances. For example, it could be used to detect antibodies in autoimmune diseases, screen for certain infections, or evaluate protein levels associated with metabolic or genetic disorders.
Common Uses and Conditions
Common reasons for this test include diagnosing autoimmune disorders, detecting infections (such as viral or bacterial), monitoring chronic conditions, or assessing genetic or metabolic issues linked to the specific substance being tested.
Sample Collection and Preparation
A blood sample is typically collected from a vein in your arm. The blood is then processed to separate serum or plasma, which is sent to the lab for testing. No special preparation is needed, but you may be asked to avoid certain foods or medications before the test if instructed by your provider.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The presence or absence of this substance can provide critical information about your health. For instance, detecting specific antibodies may indicate an immune response to an infection or autoimmune activity. Understanding these markers helps healthcare providers diagnose conditions early, tailor treatments, and monitor disease progression or response to therapy.
Frequently asked questions
What Does a Positive or Negative Result Mean?
How Often Should I Get This Test?
Are There Any Risks or Side Effects?
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