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Exposure Source Screening (Qualitative Immunoassay)

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

This test checks for exposure to certain substances (e.g., drugs, toxins, or pathogens) in your body through a simple blood sample.

Quick summary

["It helps identify potential environmental or medical exposures that may require further evaluation."]

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

Key facts at a glance

LOINC
92944-8
Short code
EXPOSURESOURCE
Synonyms
—
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

This test detects the presence of specific substances (like medications, toxins, or antibodies) in your blood using an immunoassay method. It’s designed to screen for exposure rather than measuring exact concentrations.

Why You Might Need This Test

Your healthcare provider may order this test if you’ve been exposed to certain substances (e.g., drugs, chemicals, or infections) or if you’re part of a screening program for occupational or environmental risks.

Common Uses in Healthcare

Common uses include monitoring exposure in occupational health, drug screening in medical settings, or detecting antibodies to pathogens (e.g., viruses) in research or clinical trials.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw a blood sample. It usually takes a few minutes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test provides a qualitative result, meaning it only tells whether a substance was detected or not. It’s not used to measure exact amounts or track changes over time. Results may guide further diagnostic testing if needed.

Short name

Exposure Source Test

Frequently asked questions

How long will I need to wait for results?
Results are typically available within 1–2 business days, depending on lab processing times. Follow-up instructions from your provider will be provided if additional testing is needed.
What does a positive result mean?
A positive result indicates the presence of the detected substance or marker in your blood. This may signal exposure to a specific substance or infection, prompting further evaluation by your doctor.
Can I drink alcohol before this test?
Alcohol use before the test may not affect this qualitative screening, but avoid heavy alcohol consumption if your provider has specific instructions for other tests you’re undergoing.
  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