Originally posted: January 7, 2017
Updated: June 07, 2021
I have written this post out of frustration over the rampant misinformation given to parents when they first get their children tested.
Doctors often tell parents their child’s Blood Lead Level [“BLL”] is “normal” when the level is 1, or 2, or 3 — or even 5 — micrograms per deciliter [µg/dL]. They also tell families their child’s BLL is “normal” when a test comes up with a BLL of “< 3.3 µg/dL” [less than 3.3 micrograms of Lead per deciliter of blood.] While sadly not uncommon, none one of these results actually constitute any natural or “normal” state regarding the amount of Lead in the blood of a human being, historically.
Q. What is a normal BLL? How do I know if my child’s BLL is normal?
A. There is no “normal” level of Lead in a child’s blood*.
The image above is of my youngest son Charlie’s Blood Lead Level test result from October 30, 2014. In it the doctor checked a box and left just one comment “These lab results were normal.” We then got a new doctor (actually we went back to his old doctor — who actually knew what she was talking about, when it came to Lead!)
I am sharing my son Charlie’s old test result with you as it is an example of EXACTLY the kind of test result you DON’T WANT TO GET from your doctor. There is no value to a test result like this. Again, I reiterate – there is no level of Lead in a child’s blood that should be considered “normal.”*
Historical context (simplified):
Scientific research has long shown that pre-industrial-revolution human blood Lead levels (BLLs) were in the neighborhood of 0.016 micrograms per deciliter. [The Industrial Revolution happened between 1760 and 1840.] A BLL of 4.8 is 300 times that.
MORE RECENT research shows that even that BLL of 0.016 is high (not natural) and actual pre-industrialization (pre-human-mining and ore-smelting impacts on the planet) BLL’s were significantly below that. Harvard researchers determined this by studying population BLL’s (extrapolated from bone Lead levels) from humans that lived during the Black Death (when human-created air pollution essentially was put on pause as most mining on the planet ceased because the workers in the mines (strong young men) died off – as an entire population segment).
My son had a BLL of 16.0 when he was poisoned. That is more than 1000 times the level that some might consider “natural” (over the past 5,000 to 6,000 years – since the widespread human activities of extracting metals from the earth began.) Some might argue that it is useless to look that far back as we cannot strive to meet pre-industrialization levels for pollution-related health concerns, however I feel it is very important to know this history when trying to understand context and determine what we should consider “normal.”
Aside: When did the widespread human activity of mining Lead ore start?
In searching out a good timeline as to when humans started polluting the air through mining and smelting (as a widespread global practice) I found this website – LINK. The image below is a screenshot from this link.
Given negative health impairments (infertility, birth complications, low-birthweight in newborns) have been observed in modern American women of childbearing age with blood Lead levels as low as 0.43 – I think it is easy to argue that even levels that low are not “normal”. Lead is a potent neurotoxin (in fact it is a poison that interferes with ALL biological systems, not just the brain) and all public agencies currently agree that there is no safe level of Lead exposure. In response to this agreed upon stance of the scientific and public policy communities we need to stop “normalizing” (accepting as normal) any level of Lead in the blood.
“I don’t care about history or public policy…
… I just want to know what I need to know for MY KID!”
Most Important: Get your child’s actual Blood Lead Level NUMBER
When you get your child tested, your doctor should give you the results in the form of a NUMBER. You want that number to be as LOW as possible, and ideally (no matter what) below a BLL of 1.0 (micrograms of Lead per deciliter of blood.) If at all possible that number should even be closer to (or below) 0.5. Common possible results might look like this (Items A & B below – all measurements are in µg/dL – micrograms of Lead per deciliter of blood – if you are in the United States.)
A.) You may get a “less than” reading…
Possible “less than” readings generally look like one of the options below. If you get a “less than” result (and especially if the numerical value of your test result in this case is anything greater than a “1”), you may opt to look for a second, more accurate follow-up test.
- “< 1” [µg/dL] – read as “less than one microgram per deciliter”
- “< 2” – read as “less than two micrograms per deciliter”
- “< 3” – read as “less than three micrograms per deciliter”
- “< 3.3” – read as “less than three point three micrograms per deciliter”
- “< 5” – read as “less than five micrograms per deciliter”
By far the most common “less than” reading is “less than 3.3.” The reason this is so common is that there is a testing device that many doctors have in their offices that has a low threshold of detection of 3.3 µg/dL… If you get a “less than” reading (with any number next to it) it does not mean that your child’s blood lead level is that number… it means that their result is some unspecified number that is less than that number. As an example: f your child gets a “less than 3.3” (“>3.3”) their BLL could still be a 2.0 or a 3.0 which is indicative of current exposure (and is not negative.)
B.) Depending on the testing methodology / equipment, you may instead get an actual number reading.
It is preferable to get an actual number reading from a lab or hospital or medical office that offers the lowest possible threshold of detection available in your area (you may need to do some calling around to determine which agency has the most accurate test – but I always suggest starting with calling the lab at your local Children’s Hospital.) Actual BLL test result (number) readings my own children have gotten [the highest number being the first test in 2005 — finally provided, at my insistence, months after the onset of their “mysterious” illness — after what was eventually diagnosed as “acute Lead-poisoning”]:
- 16.0 micrograms per deciliter
- 4.0 micrograms per deciliter
- 3.2 micrograms per deciliter
- 1.6 micrograms per deciliter.
- 0.8 micrograms per deciliter
- 0.4 micrograms per deciliter.
Seven (7) things you need to know (details for each of these points expounded on below):
- Request the most accurate testing methodology available (a venous draw.)
- Find out the low threshold of detection for the lab being used to analyze your sample.
- Find out the margin of error for blood Lead tests done by the lab analyzing your sample.
- Ask for your actual BLOOD LEAD LEVEL. This is a real NUMBER (whole or decimal.)
- Know your child’s BLL number (remember your number.)
- Learn and understand the federal standards for Blood Lead testing and how they relate to your number.
- Get your child tested as early as possible.
#1) Ask (in advance of your testing appointment) for the most accurate testing methodology: a venous draw.
- If at all possible the best test (with potentially the most accurate results) will normally come from a venous draw at a lab, however not all labs are equal (and there are some exceptions to this.)
- Finger-stick or toe-prick tests can be falsely high if the child’s toe or finger is contaminated with Lead dust from their environment. If you get a high finger-stick test result they will want to re-do it with a venous test anyway, so if you skip straight to the venous you save time (and potential trauma of repeated jabs to your child.)
- Call your doctor’s office in advance of your child’s BLL test and ask if they do a venous draw (from the arm) or if they normally do a finger-prick or toe-prick.
- If they tell you they only have the capability of doing a toe or finger-prick in the office – call around to other labs, clinics and hospitals in your area to find out who can do a venous draw and see if you can get your doctor to send a referral over to the organization that will do a venous draw. This is often at the local children’s hospital.
#2) Call in advance of your testing appointment and find out the “low threshold of detection” for BLL tests at the lab where your child’s blood sample will be analyzed.
Common low thresholds of detection are:
- 3.3 µg/dL
- 5 µg/dL
- 1 µg/dL
In each of the above cases the lowest possible reading for a test will be “less than” the number above (as discussed above). You want the lowest possible threshold of detection. A low threshold of detection of a Blood Lead Level 5.0 µg/dL is very high — and some of the more accurate labs have a low threshold of detection as low as 0.1 [and sometimes even lower ]…. so that’s your goal, if at all possible (as close to 1.0 or below 1.0).
My two youngest children’s last blood lead tests came up as a BLL 0.4 and a BLL 0.8. Results to this degree of accuracy are possible – and preferable, if you have access to a lab that has this capability.
#3) Ask in advance of your testing appointment for the margin of error of the testing at the lab where your sample will be analyzed.
The margin of error is normally expressed either as a percentage or as a specific number of Blood Lead Level (BLL) points. So some (the best) labs will have a very small margin of error of 10%. Some examples:
- With a margin of error of 10%, if your child tests positive with a BLL of 1.0, then you know that the result is within the range of 0.9 to 1.1.
- If they test positive with a margin of error of 10%, and the result is a BLL 10.0, then you know their number is in the range of 9.0 to 11.0
A less useful margin of error (but still possible and common) is a margin of error of 2, or 3, – or even 5 – blood Lead level points. In that case (as an example), if your margin of error is 3 points, it could look like this:
- Your child got a BLL of 4.0 so their actual range is anywhere from 1.0 to 7.0.
- Your child got a BLL of 10.0 – so the actual range is anywhere from 7.0 to 13.0
A high margin of error can be particularly confusing if you are trying to track the change in your child’s Blood Lead Level over time. You might get a BLL 10 one time, and two months later get a BLL 8 — and if the margin of error is 3.0, those two numbers could represent essentially the same level of continuous exposure for that child (with no actual change).
#4) If you aren’t provided a specific number ask for the exact number.
- When your child gets a blood Lead test result ask to see the PRINTOUT of the paperwork with their test result (if they call you with the result ask if they can email you or mail you a printout with the test result.)
- Note: nurses OFTEN (way too often, unfortunately) misinterpret Blood Lead Level (BLL) tests. They often tell parents their child’s test result is a whole number when it is, in fact a “less than” reading. So if the report says the result is “less than 2” nurses in a rush might tell you your child’s result is a 2.0. This is why you need to see the test result paperwork yourself, to make sure you know if it is a real number or a “less than” result that you are being given.
- Make sure you have the EXACT number. Is it a BLL 10? or a BLL 10.5? Not all test results will have decimals (most are given in whole numbers.)
- A test with no numerical value (and to some degree, a test with a value that is only “less than __” such as “less than 3” or “less than 5”) is not particularly helpful**
- If you are not given a number you may want to re-read the points on this post and consider having the test redone with a more accurate testing methodology, at a lab that has a lower threshold of detection and a smaller margin of error.
#5) Know your number!
- Knowing the exact number helps you to make informed decisions for your child.
- Knowing the exact number also gives you a baseline that you can compare future tests to – so you know if the child’s level goes up or down.
- By knowing if your child’s Blood Lead Level changes (with periodic testing – every 6 months or so in infancy and toddlerhood, and then at least annually through the teen years), you can pinpoint a time-frame of any exposure and therefore help identify the source of their exposure.
- This is especially useful if – in the future – they test positive at a higher level.
#6) Understand the Federal standards(& history of the issue), so you can clearly explain to your child’s doctor why they are misinformed (in the event they tell you that your child’s BLL is “NORMAL”).
- If a doctor has been practicing for a very long time (more than 10 or 20 years), they might be working with outdated standards for what they consider a concerning level of Lead in blood (i.e. misinformed).
- Specifically, they may not be aware of the current science that clearly has established that there is no “safe” level of Lead in blood.
- Your doctor may believe (again, based on an outdated standard) that as long as your child has a Blood Lead Level below some outdated reference number, (like 10.0!), they are “fine”.
- This is simply not true — and the doctor needs to do some current research, if that is their perspective.
- If your child tests positive for any Lead in their blood and your doctor says your child’s level is “Normal” – please encourage them to watch my film (which includes interviews with many of the top doctors and researchers involved with the issue of Childhood Lead poisoning): https://youtu.be/eRKlaC2EjL0
- If your child tests positive at a low level (under 5.0) and the doctor says their level is “Normal” you may also want to share this article with them: LINK.
- You may also want to share this article with them (about the impact of low levels of exposure on reproduction/conception/pregnancy/birth.)
- And this article with recent research from Harvard (about pre-industrial levels of Lead in humans.)
#7) Get a baseline Blood Lead Level test as early as possible
Even if you have no concern for exposure, I encourage all parents to get a baseline blood Lead test for their children. I wish my children had each had a baseline from an earlier test — to compare to their test results at the time they were poisoned (that would have helped us assign liability to the contractor among other potential benefits!); however, in the 9 years of my experience as a parent prior to my children’s poisoning, it was NEVER ONCE suggested by their doctors that they be tested for Lead. Every child should be routinely screened, as Lead does not discriminate — it continues to seriously impact the lives of children [and their families] in all communities, irrespective of race, color, socio-economic, geography, level of education, etc. To see what a proper Blood Lead Level test result looks like – click here.
Q. When should a child first get tested?
A. Earlier than doctors are currently recommending!
I always recommend that a child first get tested at 6 or 7 months (before they start to crawl), and then again 4 to 6 months after that first test (or as soon after they begin to crawl as you are comfortable testing them). This way, you can find out a base level for the child – at a time when they should not have had any environmental exposure (pre-crawling) – and catch any post-crawling exposure before it is prolonged (and potentially more damaging).
Of course, in order to PREVENT exposure in the first place, it is best to test the house and floors first (using dust-wipe sample testing, prior to a child inhabiting a home if possible, and definitely prior to crawling), so you can know the potential risk to the child – but I understand that is not always possible, and still encourage the Blood Lead testing scenario above, regardless of whether or not the house has been tested (as exposure can come from grandma’s house, or daycare, and other potential sources!) Here’s an article with all you need to know about dust wipe sampling.
As always, please let me know if you have any questions.
*”From modern studies, scientists know the relationship of lead in blood to lead in bones. So in 1992, a group of scientists measured lead in the bones of pre-industrial humans, for the purpose of estimating “natural background” (pre-industrial) levels of lead in blood. They concluded that the natural background level of lead in human blood is 0.016 ug/dL — so 5 ug/dL represents a level 300 times as high as natural background. A 300-fold increase in a potent nerve poison seems certain to take its toll on humans so exposed, especially if they are exposed during early childhood, when their brains are developing rapidly.” [see post: https://tamararubin.com/2017/01/toxic_lead/ ]
**The only exception – in which a test whose results are expressed as a “less than” reading should still be considered a useful screening tool is if you have the opportunity to get a finger-prick test at (for example) a free clinic – which is quick (it usually just takes about 3 minutes to get a result — using a machine called a “LeadCare2”), and will give you a low threshold Blood Lead Level of “less than 3.3”, due to the restrictions of the instrument (which was developed specifically for use as an in-the-field “screening” instrument). If you do get a result like this, you can then ask your doctor for a follow-up venous draw test to confirm the actual specific level.