Parent holding a toddler while talking with a nurse at a clinic

Blood Lead Level Explainer: What Your Result Means

A blood lead result is given in micrograms per deciliter (µg/dL), and the number CDC uses to identify children with more lead in their blood than most children is 3.5 µg/dL. Enter a result below to see how it compares with CDC’s reference value and what to ask your doctor.

In short: this explainer is educational. It is not a diagnosis, a test or medical advice, and it cannot tell you what to do about a result. Your doctor or local health department can. We do not store or send what you type.

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If someone may have swallowed something containing lead, or has symptoms that worry you, call Poison Control at 1-800-222-1222 or your doctor right away. In an emergency, call 911.

How to use the explainer

  1. Enter the number from the report. If it is in µmol/L, choose that unit and the tool converts it (1 µg/dL is about 0.0484 µmol/L).
  2. Say who was tested: a child, an adult, or a pregnant or breastfeeding person.
  3. Say how the blood was taken, if you know: a finger or heel prick (capillary) or a draw from a vein (venous).

How to read the results

CDC’s blood lead reference value: 3.5 µg/dL

In 2021 CDC lowered its blood lead reference value from 5 to 3.5 µg/dL. The value is based on the 97.5th percentile of blood lead levels in U.S. children aged 1 to 5, which means about 97.5 percent of young children tested in national surveys had lower levels. CDC is clear that it is a reference point for finding children with more exposure than most, not a health-based safe line. CDC also says no safe blood lead level in children has been identified.

So a result under 3.5 µg/dL does not mean “safe,” and a result above it does not by itself tell you how serious the situation is. It means the doctor and health department follow up: confirming the result, looking for the lead source, and deciding when to test again.

Finger-prick results need a venous test to confirm

CDC notes that a capillary (finger or heel prick) test is often the first step because it is quick, but it can read high if lead on the skin gets into the sample. CDC’s guidance for doctors is to confirm a capillary result at or above 3.5 µg/dL with a venous blood test, and the higher the result, the sooner that confirmation should happen.

Adults and pregnancy

For adults, the national surveillance case definition uses the same 3.5 µg/dL reference value, while CDC’s occupational program (NIOSH ABLES) has used 5 µg/dL to flag an elevated level in workers. CDC’s guidelines for pregnancy call for follow-up testing and steps to reduce exposure at 5 µg/dL or more. If you work with lead, are pregnant or are breastfeeding, ask your doctor what your result means for you. Our blood lead levels guide explains these values in more detail.

Questions to ask your doctor

  • Was this a finger-prick or a venous test, and do we need a venous test to confirm it?
  • When should we test again?
  • Will the health department look for the lead source at home?
  • Is anyone else in the household at risk and should be tested?

Official references

Limitations and privacy

The explainer shows what CDC’s published values say about a number. It does not know the person’s health, history or symptoms, and it does not suggest treatment. Only a doctor can interpret a result for a person. Your entry stays in your browser: we do not save it, send it or ask for your name.

Frequently asked questions

What does a blood lead level of 3.5 mean?

It is CDC’s reference value. A child at or above 3.5 µg/dL has more lead in their blood than about 97.5 percent of U.S. children aged 1 to 5. It calls for follow-up with a doctor, not panic.

Is any blood lead level safe?

CDC says no safe blood lead level in children has been identified. Finding and removing the source of lead is the goal.

Is this a blood lead level calculator?

It converts units and compares your number with CDC’s published values. It cannot calculate risk for a person or replace a doctor’s advice.

How do I get a blood lead test?

Ask your doctor or local health department. See blood lead test and how to test for lead poisoning.

Where to go next