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Serum Mercury Concentration (≥24 Hours)

Published: August 9, 2026Updated: August 15, 2026

This test measures the amount of mercury in your blood over a 24-hour period, often used to assess exposure to environmental or occupational mercury sources.

Quick summary

["Helps identify long-term mercury exposure that standard blood tests may miss."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
112113-6
Short code
MRCRAN
Synonyms
Annual mercury IgE Qn IA
Category
chemistry
Sample
serum
Container
Serum separator tube (SST, gold-top) or plain red-top tube for serum; plasma lithium heparin or EDTA tubes acceptable
Units
N/A
Ref low
0
Ref high
0.35
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
Immunoassay (e.g., Fluorescence Enzyme Immunoassay [FEIA], Chemiluminescent Immunoassay [CLIA], or Enzyme-Linked Immunosorbent Assay [ELISA])
CPT
86003
SNOMED
395141001
Specimen volume
0.5-1 mL serum or plasma
Stability
Serum stable for 7 days at 2-8°C; stable for 4 weeks at -20°C; avoid repeated freeze-thaw cycles
Hemolysis max
200
Lipemia max
100
Icterus max
40
TAT
24–72 hours
Order
routine

Why This Test Matters

Mercury is a heavy metal that can build up in the body over time, especially from certain foods, industrial exposure, or contaminated water. While short-term spikes may not show up in a single blood test, this 24-hour measurement provides a clearer picture of ongoing exposure. This is particularly important for people with prolonged contact with mercury-containing products or those living in areas with known contamination.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw. Wear comfortable clothing and plan to rest afterward, as drawing blood can make you feel lightheaded.

What the Results Mean

Results are typically reported as a concentration (e.g., micrograms per liter). Higher levels may indicate recent or chronic exposure, which could affect your health over time. Your doctor will interpret results in the context of your medical history and other tests.

Common Causes of Elevated Mercury Levels

Exposure can come from mercury-containing dental fillings, certain industrial jobs, or consuming fish from contaminated waters. Smoking or exposure to mercury vapor from household products (like old thermometers) may also contribute.

Reference range

Class 0: <0.35 kU/L (Negative); Class 1: 0.35-0.70 kU/L (Equivocal/Low); Class 2: 0.71-3.50 kU/L (Positive); Class 3: 3.51-17.50 kU/L (Positive); Class 4: 17.51-50.00 kU/L (Strongly Positive); Class 5: 50.01-100.00 kU/L (Strongly Positive); Class 6: >100.00 kU/L (Strongly Positive)N/A

Specimen: serum

No special preparation required. Patient does not need to fast. Antihistamine use does not interfere with IgE testing. Recent allergen exposure may influence results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated mercury levels can pose risks to organs like the kidneys and nervous system, especially in sensitive populations (e.g., pregnant individuals, children). Your doctor may recommend further testing or lifestyle changes if levels are elevated.

Short name

24-Hour Mercury Level (Serum)

Frequently asked questions

Why did my doctor order this test?
Your doctor may recommend this test if you have symptoms like headaches, nausea, or neurological concerns, or if you work in an industry with mercury exposure. They may also order it if you’ve had recent exposure to mercury-containing products or live in an area with known contamination.
What should I do if my mercury level is high?
If results are elevated, follow your doctor’s advice, which may include reducing exposure to mercury, avoiding certain foods (like large fish), or undergoing chelation therapy in some cases. Avoid self-treating without medical guidance.
Does this test differ from a standard blood mercury test?
Yes. Standard blood tests measure mercury at a single point in time, while this 24-hour test accounts for ongoing exposure over a full day, providing a more accurate picture of your body’s mercury burden.
  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 15, 2026. · Read our editorial policy