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Serum or plasma state of a substance (qualitative assessment)

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

This test evaluates whether a substance in your blood is present or absent, rather than measuring its exact amount.

Quick summary

["It helps determine if a substance is detectable in your bloodstream."]

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

Key facts at a glance

LOINC
68488-6
Short code
STATE
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 assesses the qualitative state (presence or absence) of a specific substance in your serum or plasma. Unlike quantitative tests that provide a numerical value, this test simply indicates whether the substance is detectable or not.

Why It’s Used

Qualitative tests like this are often used for initial screening to quickly identify whether a substance—such as certain proteins, hormones, or pathogens—is present in your blood. They can help guide further diagnostic testing if needed.

Sample Collection and Preparation

A blood sample is drawn, typically from a vein in your arm. The blood is then separated into serum (after clotting) or plasma (after centrifugation), and tested for the presence or absence of the substance.

What to Expect Before the Test

No special preparation is usually required, but you may be asked to fast for 8–12 hours if the test involves blood collection for serum/plasma. Avoid smoking or consuming alcohol for a few hours before testing if advised by your provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How long will I need to wait for results?
Results are typically available within a few hours to a couple of days, depending on the lab’s processing time. Your healthcare provider will discuss the results with you during your follow-up visit.
What does a positive or negative result mean?
A positive result means the substance was detected in your blood. This may prompt further testing to determine its cause or level. A negative result means the substance was not detected in this sample, but other factors (like timing of testing or sample quality) could affect accuracy.
Can I get this test at home?
Some qualitative tests for substances like pregnancy hormones or certain infections can be done at home using over-the-counter tests. However, blood-based qualitative tests (like those for serum/plasma) are almost always performed in a clinical lab and require a healthcare provider’s order.
  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