Finding a lab to test for lead – not as simple as it should be!
The two biggest labs in the U.S., Labcorp and Quest, (these labs exist as walk-in labs, as well as being contracted by many hospitals) will not report results any lower than a “less than 3”. (Less than a blood lead level of three micrograms per deciliter.)
Why is this important?
Labs and many doctor’s offices will tell you that anything under a 5 is effectively “negative for lead”, or at least is not a level to be concerned about. A slightly more informed doctor’s office might flag a level of 3 and recommend a follow up test to see if it is going down on its own. This is because the CDC has chosen a level of 5 as its current “level of concern” (a number which is actually moving target that is expected to go down over time, based on population levels of lead in blood), prompting healthcare workers to often dismiss anything below that level. At the same time the CDC has clearly stated that “there is no safe level of lead in a child’s blood.”
Note: fairly recently the federal level of concern was a blood lead level (BLL) of 10 micrograms of lead per deciliter of blood and in some states the level of concern has recently been as high as a BLL 15, so depending on where you live – your doctor may not be concerned if you child has a BLL of 9.0 or even 11.0 – because they are not up on the current (well documented) science and understanding about the impact of even low level lead exposure (exposure levels today that would have been considered “trace” or “background” levels in previous decades.)
That said, true blood lead level readings that are an actual number “below 3” are not an acceptable blood lead level.
No level of lead is safe in a child’s blood.
An actual blood lead level of 3.0 (or 2.0 or 1.0 for that matter) does indicate exposure. A BLL of “less than 3” (or “less than 2” or “less than 5”) could be a 1 or a 1.9 or even a true zero, so it is important to know what kind of testing was used and to get a real number for your child’s blood lead level if you can.
In some cases the only testing capabilities your doctor (or a mobile clinic) may have is a test that reads “less than 3.3.” Parents often come to us with the misunderstanding that this means their child tested positive at a BLL 3.3. It is important to understand that “less than 3.3” could be any number under 3.3. If you get a reading along those lines and you want to get a follow up test to determine the actual number because you know you have a potential lead exposure source or incident, it is sometimes possible to get a referral to your local children’s hospital where they are likely to have more sensitive testing equipment and capabilities.
In addition to finding out the actual number you should also inquire about the margin of error for the testing methodology used by a lab. A blood lead level of 4.0 with a margin of error of 4.0 BLL points could be a 0.0 or could be an 8.0 (micrograms of lead per deciliter of blood.) The same result (blood lead level 4.0) with a lab that has a margin of error of 10% would be a result in the range of 3.6 to 4.4 micrograms per deciliter.
To avoid multiple blood draws it is best to get the most accurate test available to you with the smallest possible margin of error – which is why it is good to research labs if you have time, before you get your child tested.
“Low level exposure” and why it matters
Below is a link to one of Tamara’s favorite articles about the impact of low-level lead exposure.
Two critical points you will read here are:
- The “natural background level of lead in human blood is 0.016 ug/dL.” In our industrialized world, it may be very hard if not impossible to have such a low level. That does not mean that a higher level should be characterized as “normal.” The CDC’s “level of concern” of 5 ug/dL is in fact 300 times higher than the “natural background level.”
- We already know that there is brain damage that occurs at levels lower than 10 ug/dl. But there are health impacts even as levels rise above 1. Below is a quote from the article.
“** Reduced height and head circumference as blood lead levels rise above 1 ug/dL.
** Delayed sexual maturation. Two studies observed late puberty in girls with blood lead levels in the range of 2 to 5 ug/dL. This seems to indicate that lead is interfering with the endocrine (hormone) system.
** Dental caries (popularly known as “cavities” in teeth) were more likely to develop as a child’s blood lead level rose from 1 to 3 ug/dL.
And a study too recent to have been included in the Appendix has shown that a child is 4 times as likely to have attention deficit hyperactivity disorder (ADHD) when blood lead levels reached 2 ug/dL or greater, compared to children with lead at 1 ug/dL. “
Please take the time to read the article, and click through to the excellent references provided.
Ok, I get it. But how do I find a lab with a lower detection limit than 3??
This question has come up many times on our Facebook groups, including our private group for parents whose children or homes have tested positive. Labcorp and Quest DO NOT report below 3, or rather they will report a “less than 3”. As we said above, “Less than 3” could mean 2.9, or it could mean 0.5. Those are very different numbers indicating a very different course of action
I have personally researched a half dozen labs across the country to try to find one with the capability of consistently giving a more accurate result:
Here is the message we received from Doctor’s Data Lab:
“In laboratory analysis one does not define any measurement as zero – it comes down to what is the detection limit for the instrument and method being used. For Lead, DDI’s detection limit is 0.02µg/dL which is much lower than the Reference Interval of <3µg/dL. Blood Lead is highly regulated and the standard of imprecision for Lead is 10%. DDI’s Total Allowable Error is less than 10% so we are well within acceptable limits.”
This means, yes, they meet the criteria! The test they show online is called “Whole Blood Elements” and tests for 20 different elements. However, Doctor’s Data did tell us your doctor can order a single element! (lead only) (https://www.doctorsdata.com/whole-blood-elements/ )
Typically, a doctor’s office will have an account with this lab and will have their kits on hand and fill out the requisition form. Then you take the kit to any lab (including Quest) for the blood draw, and that lab will mail the kit directly to Doctor’s Data. The results then go back to your doctor’s office. This lab is a popular one among integrative or functional medicine doctors.
A parent in our private Facebook group recommended a lab called NMS. She had a personal experience with this lab. This lab’s detection limit is 0.5 and their “mean variance” is 2%.
Her doctor wrote on the order that she only wanted the blood sample sent to this particular lab, and she reminded everyone she dealt with along the way at the lab. This was a hospital lab who normally sends out to Quest.
Another member of the group attempted to do the same thing. In her case the blood draw was performed at Quest, and the sample never made it to NMS! That tells us you really do need to stay on top of them and remind everyone – and mistakes still can happen.
Another private group member used Geisinger medical laboratory in Danville PA with success. Their detection limit is 0.5 and we are not able to confirm their margin of error.
It seems that some children’s hospitals do have a low detection limit. This has been the case (but could change in the future – so still ask!) for the labs used by Portland Providence Hospital and Doernbecher’s Children’s Hospital in Portland , OR – however the doctor does need to make sure to request the sample to be tested to the lowest possible limit of detection and for an actual number to be reported (as opposed to a “less than” range.)
It is worth understanding this issue and asking your doctor and your lab about it. We have had members ask these questions and get wrong information from both doctors and from labs. You may have to push to be able to speak with someone in the lab department, or to get the information in writing. Also, be prepared to answer your doctor’s question: “Why do you need a lower detection limit?” [A. Because latest available science shows that no level of lead is safe and I want to know my child’s actual blood lead level now so that I can have a reference-point/base-line in case it goes up in the future.]
The questions you want to ask the lab are:
- What is your detection limit? (the lowest number they will report)
- What is the margin of error?
- What is the turn-around time for the test-results? (How quickly will I have the results?)
If anyone has experiences to report about these labs or any others, please do share below!