I got my lab results back and was brought to a complete standstill.  My ferritin level – which indicates how much iron your body has stored – was 4.

To give you some context, the new threshold for diagnosing iron deficiency in adults is 30 or below; I was not only below that number but was living in the basement underneath it.

What surprised me the most, being a doctor, was my hemoglobin.  It wasn’t low.  If you only looked at that number, you would have told me that I was okay and sent me on my way.

I’m going to try to keep the iron puns to a minimum, but it’s a bit ironic that a doctor who talks to families every week many times about anemia should fail to realize how depleted her own body had become.

There are two reasons I want to talk about this now.  The first is that the American Society of Hematology has just come out with new guidelines on diagnosing iron deficiency in adults and young children.  The second is more personal: having been a patient myself and in the situation described has changed the way I think about iron in my own patients.  

During my daughter’s (second and last) pregnancy; I had iron deficiency anemia. That meant my hemoglobin and ferritin were low. I was a candidate for iron infusions in pregnancy and it helped my energy and mood greatly. Postpartum, I had my hemoglobin checked which always came back normal, but never had my ferritin checked. 

Time went on, life went on, life with two and a business became busy. I have always been an anxious person but for a year I was having palpitations. I chalked it up to anxiety. Last year, I started noticing exercise intolerance. I used to do track-and-field when I was younger and now running and any cardio would leave me winded. I felt deconditioned and I couldn’t imagine this was only due to age. I have a trainer and I kept expressing to him that I was so winded and he also became concerned given my inability to complete basic cardio.

I decided to see a cardiologist. The appointment wasn’t for another month due to availability and switching of insurances. I also noticed extreme fatigue to the point I needed to nap every day for hours and still felt unrested. At night, I tossed and turned. I thought it was anxiety and sort of gaslit myself into believing this was all mental health related. And at the beginning of this year I began having brain fog. “Mom brain? I thought. This brain fog was so significant that I couldn’t even get writing or work done efficiently. What used to take me 1 hour was taking me 4. I was more forgetful and my son even said “Mommy why are you forgetting everything?” And then, there was the hair loss. A journey I’ve been dealing with for a year as well and I started using minoxidil foam, tretinoin, and got a new shower filter and have been seeing more growth. 

While I was awaiting the cardiologist appointment, I started having a GI issue. Steattorhea after eating red meat. Yup, pooping oil my friends. TMI, I know, but it’s important to the story so bear with me. This was startling to say the least given I have prided myself on having a rock-solid GI system WITH no issues besides postpartum ileus related to complications during delivery. Needless to say, I was worried. I saw a GI doctor, they ran all the labs: hemoglobin celiac, stool studies, comprehensive metabolic panel….everything. Everything came back normal. My GI doctor said to monitor and if symptoms continue; we would do an endoscopy and colonoscopy. 

I started seeing an acupuncturist again after two years to see if she could help with the extreme fatigue, restlessness, palpitations “anxiety,” and stomach issues with no medical reason. After two sessions, the steatorrhea went away. Fluke? I don’t know. Coincidence? I don’t think so. In any case, I was ecstatic. I could eat meat again in moderation without looking at the toilet in horror. I began eating red meat in moderation; but I knew I wanted to evaluate this further. 

After a horrible attempt and finding a primary care clinician in my area who 1. Isn’t a concierge doctor and 2. Takes my insurance; I decided to self order labs on Quest. Yes, it’s an option and yes it’s expensive. I ordered a Vitamin B12, Vitamin D, Thyroid panel, and FERRITIN. I wanted to see if there was anything else causing my extreme fatigue. 

The next day, I checked my labwork. Everything was normal except…the ferritin. It was a 5. I immediately texted my group of girlfriends; some of whom are primary care doctors or internists who were surprised I was still functioning. I made an appointment with a hematologist–and again another 4 week wait due to travel and availability. I had the appointment and she was also very concerned about the ferritin. She wanted me to repeat my labs again so insurance would cover the infusion (they need a level within 30 days); so back to the lab I went. The repeat ferritin: a 4. I got my iron infusion scheduled and got 1 infusion of monoferric on August 19th. My repeat labs a month later showed a ferritin of 107. 

I ended up canceling the cardiology appointment when I found out my ferritin was 5. Two days after my infusion, my palpitations were gone. Three days after, I worked out and I no longer had exercise intolerance, and my hair is actually growing more now. 

In retrospect, much of how I was feeling could be easily dismissed.  I’m a working mom, and tired is essentially my usual state.

The entire experience taught me how easy it is to get used to feeling drained, especially as a parent since we are expected to be tired we no longer ask why.

It taught me an even more uncomfortable lesson as a physician.  If the laboratory results had been interpreted the way so many of us were taught to interpret them, with the main emphasis on hemoglobin, it would have been easy to have missed the final result.

These two medical terms are often treated as if they have the same meaning, but they do not, and the distinction is important.

Ferritin is like your savings account and hemoglobin is like your checking account.

Each day your body draws on its checking account to pay its bills.  When the checking account begins to fall low, your body then quietly moves funds from your savings to meet the obligation.

So what occurs when your savings account gets depleted? For some time, nothing seems wrong since the checking account remains full.  You can empty your savings over a period of months while the checking account appears completely normal.  Only when the checking account eventually fails does it turn out that the savings has been zero for some time.

In real life:

Iron deficiency indicates that your savings (ferritin) is low even if your hemoglobin appears normal.

Iron deficiency anemia means that your savings are empty and your checking account is now overdrawn; the level of hemoglobin is decreased.

Anemia is usually the phase that comes about after another problem had already been present from much earlier on.

And iron is not merely used in red blood cells.  The American Society of Hematology also states that it is required by the brain, the immune system, the muscles, the skin, the hair, and the nails, making it one of the reasons why a person may experience the effects of low iron before the anemia appears on a blood test.

That is also the reason why a blood count on its own has limitations, since the US Preventive Services Task Force has pointed out that hemoglobin is not a sensitive indicator of iron deficiency because mild deficiency may fail to affect hemoglobin at all.

It has been a big year for iron, with two large groups issuing updates to their guidance just a few months apart.

Earlier this year the American Academy of Pediatrics issued a new clinical report, which takes the place of its earlier 2010 recommendations concerning iron deficiency in infants, children, and teenagers. The previous guidelines had been concerned with screening for anemia in children aged 3 years and under, while the new report suggests that screening could be carried out using both a complete blood count (CBC) and a ferritin level. The type of test is determined by age and individual risk factors.

The previous AAP guidance already recognized ferritin as a useful test for iron deficiency, particularly when a child had risk factors or an abnormal hemoglobin. (I was already doing this). But the 2026 report goes further. It places much more emphasis on finding iron deficiency before it progresses to anemia, expands screening recommendations across childhood and adolescence, and more clearly incorporates both a CBC and ferritin into laboratory screening based on a child's age and risk factors.

On September 16, 2026, the American Society of Hematology (ASH) issued new guidelines for the diagnosis of iron deficiency in adults, young children, menstruating people, those who are pregnant, and people with inflammation. The guidelines are based on a straightforward concept: iron deficiency is diagnosed whether or not anemia is present.

The main change is that the ferritin cutoff values have been increased according to ASH's new thresholds:

The AAP report is very similar in its recommendations for children aged 10 and under. It adopts a ferritin level of 20 or below for those aged 11 and over. It also suggests that all teenage girls who are menstruating should have a CBC and ferritin level drawn at least 1 year after their first period, no later than by the age of 14.

For years the ferritin cutoffs many of us use were around 10 to 12, and the AAP report notes that those longstanding thresholds were based on very small studies. ASH also points out that many lab reference ranges include values that are actually in the deficit range. In plain terms a child could have a ferritin in the teens and on some lab reports it might not have been flagged at all.

ASH believes that as many as 70% of iron deficiency cases could be overlooked in high-risk groups, mainly due to limited screening and inconsistent reference ranges. Teenagers provide a clear illustration of the situation. A study published in JAMA, which examined U.S. females between the ages of 12 and 21, revealed that almost 40% had iron deficiency, whereas only about 6% had iron deficiency anemia. More than a quarter of the girls who had not yet started their periods were also iron deficient.

If we look only for anemia, then we will only identify a small portion of children who, in fact, have low iron levels

That's where it becomes complicated. Since iron deficiency usually doesn't turn up with a nametag, the symptoms can be mild and a great many of them overlap with normal childhood stuff.

Here's the tough part: there are many other possible causes for each of these symptoms. A toddler who eats only three bites of dinner is typically just a toddler. A tired teenager might be one who has been on their phone until 1 am. I'm giving you this information so that you'll know what to look out for. A checklist won't be able to make the diagnosis for you.

What makes me look closer is when symptoms stack up, stick around or show up in a child who also has a risk factor.

This is the part that I believe many parents have never come across.

Iron is involved in the way the brain uses dopamine, a chemical messenger that has a role in movement and attention. When iron levels are low some children experience difficulty with sleeping and with concentration.

Restless legs and restless sleep. It is believed that about 2% to 4% of children and teenagers have restless leg syndrome and other conditions known as periodic limb movement disorder. Children generally do not describe it in the same way that adults do. They may say their legs feel buggy or that they just have to move. Parents frequently note that a child cannot settle down when going to bed and is found lying on their side in the morning.

It's also in this area that the figures can become confusing. In the field of pediatric sleep medicine a higher ferritin level is often used than the general diagnostic threshold for iron deficiency. According to the guidelines of the American Academy of Sleep Medicine, iron supplementation should be given to children who have restless legs and whose ferritin level is below 50. A child with a ferritin of 40 might not satisfy the latest definition of iron deficiency but for a child who has a particular sleep disorder, doctors might still decide to treat them at that level (since it appears that the brain requires more iron in order to alleviate those symptoms).

Attention and behavior. It has been found that, on average, children with ADHD have lower ferritin levels than children without. However it is only an association and a recent study from 2026 concluded that ferritin may be of some help for certain groups of kids but is not capable of serving as a diagnostic or indicator of the severity of the ADHD.

When the child's history matches, iron deficiency should be included on the list of possible causes. That list is what doctors refer to as the differential. Iron should be placed on it in particular where the risk factors are present, without, however, becoming the default explanation for every difficult afternoon. A weary body often seems very much like a difficult child. Sometimes what appears to be defiance or a short temper is actually a child who's been running on an empty tank and other times it's something completely different. The goal is to remain curious enough to investigate and at the same time be grounded enough not to jump to conclusions.

If we go back to the bank analogy, the Complete Blood Count (CBC) mainly shows us the checking account. It gives information regarding hemoglobin and red blood cells but it doesn't tell us how much is in the savings account.

That is the reason why relying solely on a CBC may fail to detect a child whose iron stores are decreasing. And that is why the AAP report now recommends that both a CBC and ferritin be carried out together as part of a routine screening for infants, young children, and menstruating teenagers.

Ferritin and sometimes other iron studies can give us the extra information we need when:

I'm going to be honest about something.

In my experience over the years, I have come across cases where it would have been appropriate to check a patient's ferritin level even though their hemoglobin was normal. For example:

In some of those situations a normal hemoglobin level probably gave me more reassurance than it ought to have. And now we know better–CHECK A FERRITIN. Especially if a child is having behavioral or other issues that could be iron deficiency. 

I gain a great deal of knowledge from these cases in which something was overlooked, rather than from those in which things turned out smoothly. The evidence in the guidelines keeps on changing so our approach to patient care should as well.

I'm saying this to you so that you realize that it's a good thing when doctors revise their opinions. It shows that the system is operating as it should and your clinician is adapting to do better.

Sometimes yes and other times no.

It isn't necessary for every child who has poor sleep or strong emotions to have blood tests. Since a needle poke isn’t always a pleasant experience for children and the testing should be aimed at answering a real question, it's reasonable to bring up iron testing with your pediatrician when:

What I'd like parents to understand is that ferritin must be interpreted in the context of other factors. Ferritin has a tendency to please people. It increases when the body is battling an infection or managing inflammation, which can make the iron stores appear better than they actually are. That is one of the reasons why the ASH established a much higher cutoff level for adults who have inflammation. A ferritin level measured during a severe viral infection might not give the whole picture.

In some cases the pediatrician will look at the CBC, the ferritin, the transferrin saturation, and the other iron test together. I will repeat the test when the child is feeling better.

I can see how tempting this may be. Suppose you come across a piece of content on the internet or in this newsletter. Your child is tired and there's an iron gummy on the shelf at the pharmacy. In that case I would quietly urge you to hold off. Iron is not a harmless supplement.

The FDA mandates that iron products include a warning stating that accidental iron overdose is the leading cause of fatal poisoning in children under the age of 6. Iron pills resemble candy quite closely so if you have iron at home, such as prenatal vitamins, store it in a locked place and keep it out of reach. Excess iron accumulated over a long period can be an issue and in some cases people have conditions which cause their bodies to hold onto too much iron.

When we find iron deficiency, with or without anemia, we have two goals: replenish the missing iron and figure out why the iron is low.

Sometimes we treat first and then watch what happens. If iron levels respond well and stay up, that gives us useful information. This is essentially what is happening with me right now. After my iron infusion, my ferritin jumped from 4 to 107. Now we monitor to see whether I can maintain those iron stores with my usual diet or whether they start dropping again. If they fall, that tells us we need to look harder for an ongoing source of iron loss or a problem absorbing iron (I will likely get a colonoscopy and endoscopy since no obvious gynecologic issues). 

Depending on the person and their history, we may also investigate the cause right away. Some of the big things we think about are:

The answer will not be the same for everyone. A toddler drinking 40 ounces of milk a day has a very different likely explanation than a teenager with heavy periods or an adult whose ferritin keeps dropping despite adequate iron replacement. The goal is to replenish the iron while also asking, why did the savings account get depleted in the first place?

Your clinician or your child’s clinician should be your partner in figuring this out. 

After my infusion, my ferritin jumped from 4 to 107. I recently met with my clinician to go over those results, and since my iron stores and hemoglobin are both in a good place, I'm not taking any iron supplements right now. My part of the plan is to eat a varied diet with plenty of iron-rich foods and let my body show us whether it can hold onto what we put back.

The working theory is that pregnancy and delivery drained my savings account, and because my ferritin was never checked postpartum, it never fully refilled. My diet alone couldn't catch up. If that's true, my levels should stay steady now that we've topped them off.

So we're testing that theory:

I'm sharing the details because the infusion was a big step, but it wasn't the finish line. The follow-up is where we find out why this happened. A number that's slowly sliding is worth paying attention to, even if the lab report doesn't flag it yet. Going back to the bank analogy, a savings account that keeps shrinking matters before it hits zero.

And I'm finding that so many women aren't getting this part. They get iron once, feel better, and never hear about it again until the symptoms creep back. If you've been treated for low iron, it's fair to ask your clinician two questions: When are we rechecking? And what result would change the plan?

Once iron deficiency has been confirmed and you and your clinician have a plan for figuring out why it happened, the next goal is rebuilding those iron stores.

Food is a great place to start. Iron-rich foods include red meat, poultry, seafood, beans, lentils, tofu, eggs, iron-fortified cereals, and dark leafy greens. There are two forms of dietary iron: heme iron, which comes from animal foods and is more easily absorbed, and non-heme iron, which comes mostly from plant foods and is not absorbed quite as easily.

Here's a simple trick that can help: pair plant-based iron-rich foods with vitamin C. Vitamin C helps the body absorb non-heme iron more effectively. Think lentils with tomatoes, iron-fortified cereal with strawberries, beans with bell peppers, or spinach with a squeeze of lemon.

But food alone may not be enough once someone is truly iron deficient. Depending on the ferritin level, symptoms, age, underlying cause, and whether anemia is also present, a clinician may recommend an oral iron supplement or, in certain situations, IV iron.

There isn't one "best" iron supplement for everyone. Different forms contain different amounts of elemental iron and can have different side effects, especially constipation, nausea, or stomach discomfort. The dose for a child also depends on their weight and whether we're preventing deficiency or actually treating it.

That's why I don't recommend grabbing an iron gummy and guessing. Talk with your clinician about whether supplementation is needed, which product and dose make sense, how long to take it, and when labs should be checked again.

What I’m changing after my own experience and these guidelines

Between my own ferritin level of 4 and these latest guidelines, I've recently been thinking a great deal about iron deficiency and have decided to adopt the following points:

What does the best available evidence indicate? It shows that iron deficiency is common, frequently goes unnoticed, and doesn't have to be accompanied by anemia to be significant. What does my clinical experience tell me? The families who had the greatest impact on me were generally those in which the first response wasn't the complete answer and now I can contribute a third perspective based on my own laboratory results.

Medicine is called a practice because we're supposed to keep learning and changing as the evidence changes. I'd much rather tell you I've updated my thinking than pretend I had it all figured out years ago. If your child has symptoms or risk factors that fit, it's okay to ask about ferritin. If your child seems fine and is growing and eating well, you don't need to go looking for problems. The goal is thoughtful testing and the right child with a plan for what we'll do with the answer.

I'd love to hear from you. Have you or your child ever been told your labs were normal but something just didn't feel right? Hit reply and tell me what happened.

I break down why coughs and cold symptoms often worse at night and share practical and safe remedies (saline, careful suctioning, cool-mist humidifiers and steam showers) to help manage congestion. I show true respiratory distress examples such as head bobbing, nasal flaring and chest retractions. I’ll walk you through critical warning signs and when to call the doctor or seek immediate medical evaluation.

Dr. Mona will answer these questions in a future Sunday Morning Q&A email. Chances are if you have a parenting concern or question, another parent can relate. So let's figure this out together!