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Serum or plasma substance concentration (unspecified analyte) measured by immunoassay

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

This test measures a specific substance in your blood using a sensitive antibody-based test. It helps detect or monitor certain conditions, such as infections, autoimmune diseases, or metabolic disorders.

Quick summary

["This test helps diagnose or track conditions by identifying small amounts of specific substances in your blood."]

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

Key facts at a glance

LOINC
14841-1
Short code
IH Stn Spec
Synonyms
IH Stn Spec
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
iron-hematoxylin-stain
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 presence or level of a particular substance in your serum or plasma. The method used is an immunoassay, which works by measuring how much of a specific antibody binds to your substance. This can include proteins, hormones, or other molecules that may be elevated or altered in disease states.

Why It’s Done

Your healthcare provider may order this test to diagnose or manage conditions like infections (e.g., certain viruses or bacteria), autoimmune disorders (e.g., rheumatoid arthritis), or to check for exposure to toxins or medications.

Common Uses

This test is often used as part of a screening or confirmatory process. For example, it may be used to detect early signs of inflammation, monitor treatment effectiveness, or rule out hidden causes of symptoms like fatigue or unexplained weight changes.

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 a specific analyte related to blood sugar or fats. Wear comfortable clothing and plan to stay for about 15–30 minutes while blood is drawn.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How long will it take to get my results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the findings with you during your follow-up visit.
What does a ‘positive’ or ‘negative’ result mean?
A ‘positive’ result indicates the substance is present at a detectable level, which may suggest an active condition or exposure. A ‘negative’ result means the substance was not found in the sample, but this does not always rule out the condition entirely. Your provider will explain what these results mean for your specific situation.
Can I eat or drink before this test?
Most of the time, you can eat and drink normally unless your test involves a specific analyte (e.g., glucose) that requires fasting. Always follow your healthcare provider’s instructions for the day of your 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