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Serum or Plasma Mass Concentration of Inorganic Iodine

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

This test measures the amount of iodine in your blood, which is an essential mineral often added to food and used in medical treatments.

Quick summary

["Iodine levels help assess thyroid function and prevent deficiencies."]

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

Key facts at a glance

LOINC
23254-6
Short code
M arginini Ab Ser Ql CF
Synonyms
M arginini Ab Ser Ql CF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
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 Is This Test Done?

Your healthcare provider may order this test if you have symptoms of iodine deficiency (such as fatigue, weight changes, or thyroid issues) or if you’re receiving iodine treatments (like radioactive iodine therapy). It can also be part of routine monitoring for patients with thyroid disorders or those on iodine-supplemented diets.

What to Expect Before the Test

No special preparation is usually needed. You may fast for 8–12 hours before the test if instructed, but this depends on the lab’s protocol. Bring any medications or supplements you’re taking to your appointment.

How the Test Is Performed

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it’s usually over quickly. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to standard reference ranges for iodine in blood. Abnormally low levels may indicate deficiency, while high levels could suggest overuse of iodine-containing medications or supplements.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Iodine plays a critical role in thyroid hormone production. Low levels can disrupt metabolism, cause goiter, or worsen symptoms of hypothyroidism. High levels may indicate thyroid dysfunction or excessive iodine intake, requiring medical evaluation to adjust treatment.

Short name

Iodine Level

Frequently asked questions

What causes iodine levels to be checked?
Iodine levels are checked if you have symptoms like unexplained weight changes, fatigue, or goiter (a swollen thyroid), or if you’re on iodine-based treatments (e.g., radioactive iodine therapy). Your doctor may also order it if you live in an area with iodine-deficient soil or consume little iodized salt.
How often should I get this test?
Frequency depends on your health condition. For example, people with thyroid disorders may need monitoring every few months, while others may only need it once a year or as directed by their doctor.
Can diet affect iodine levels?
Yes, diet plays a role. Consuming too much iodine from supplements, seafood, or iodized salt can raise levels, while a diet low in iodine may lead to deficiency. Always follow your doctor’s guidance on iodine intake.
  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