You’re exhausted. Your hair is thinning. You can’t concentrate. You’re breathless walking up a flight of stairs. You go to your doctor, they run some bloods, and the result comes back: “Everything is normal.”
But you still don’t feel great. And here’s the thing: you’re probably right.
Iron deficiency is one of the most common findings in my practice, particularly in women. And it’s one of the most frequently missed, not because doctors aren’t looking, but because we’ve been relying on reference ranges that don’t tell the full story.
The Problem With “Normal”
When your blood results come back, your ferritin level (the protein that stores iron in your body) is compared against a reference range. In most South African laboratories, that range sits somewhere between 30 and 150 for women. So if your ferritin comes back at 34, it technically falls within the reference range. Your report says “normal.” Your doctor moves on.
But here’s what most people don’t realise: those reference ranges are built from population-level data. They reflect what’s statistically common in a large group of people, many of whom may already be unwell, chronically inflamed, or iron-deficient themselves. “Common” and “optimal” are not the same thing.
A ferritin of 34 might be common. But for a woman who is menstruating, exercising, working full days, and trying to function at her best, it is far from optimal.
What the Research Actually Shows
There is growing evidence, particularly in sports medicine, that aiming for a higher ferritin level meaningfully improves performance, energy, and recovery. Studies in athletes have demonstrated that a ferritin below 50 can impair endurance and cognitive function, even when haemoglobin (the number most doctors focus on) is still within range.
This matters because you don’t have to be an athlete for this to apply to you. If your body is running on low iron stores, you’ll feel it. The symptoms are real, even if your blood test looks “fine” on paper.
The Symptoms That Should Raise a Flag
Iron deficiency doesn’t always look the way you’d expect. Fatigue is the most common symptom, but it goes well beyond feeling tired. I regularly see patients with hair thinning, brain fog, breathlessness with mild exertion, restless legs at night, heart palpitations, brittle or spoon-shaped nails, low mood, frequent infections, cold hands and feet, and cravings for ice or starch (known as pica).
If several of these resonate with you and your ferritin is sitting in the low “normal” range, the number and your symptoms deserve to be taken seriously together.
It’s Not Just About Ferritin
A proper iron assessment doesn’t stop at ferritin. I run a full iron panel (serum iron, transferrin, transferrin saturation, and total iron-binding capacity) alongside a full blood count. This gives a much more complete picture of how your body is using and storing iron.
Importantly, ferritin is also an acute-phase reactant, meaning it rises in response to infection, illness, or chronic inflammation. This can mask a true deficiency by making ferritin appear falsely normal or even elevated. Without the full panel, you can miss it entirely.
When Supplementation Isn’t Enough
For many patients, oral iron supplementation is enough to bring levels up over time. But for those with very low ferritin, heavy menstrual bleeding, or poor gut absorption, oral iron simply doesn’t move the needle fast enough. In those cases, iron infusion is a reasonable option, and the threshold for considering one can be lower than you might think, especially when symptoms are significantly affecting quality of life.
Replacing Iron Is Only Half the Job
Here’s something that often gets missed: finding iron deficiency is not the end of the investigation. It’s the beginning of one. The next question should always be why are you iron deficient?
For a woman who menstruates regularly, particularly with heavy periods, the answer is often straightforward. Menstrual blood loss is the most common cause of iron deficiency in premenopausal women, and it makes physiological sense. But it’s not the only cause, and assuming it is can mean missing something important.
There’s a long list of conditions that can drive iron deficiency by impairing absorption or causing occult (hidden) blood loss. These include Helicobacter pylori infection, a common and treatable bacterial infection of the stomach that directly interferes with iron absorption. Intestinal parasites, including hookworm, are another cause particularly relevant in the South African context. Autoimmune gastritis, coeliac disease, inflammatory bowel disease, and other conditions affecting the gut lining can all do the same.
Even medications can play a role. Long-term use of proton pump inhibitors reduces stomach acid, which is essential for converting dietary iron into the form your body can absorb.
If I find an iron deficiency that doesn’t have an obvious explanation, or one that recurs despite adequate replacement, I investigate further. Because replacing iron without understanding why it’s low is like mopping the floor while the tap is still running.
Why This Matters
Iron is not a luxury nutrient. It carries oxygen to every cell in your body, supports your immune system, your brain function, and your energy production. When your iron stores are depleted, your body can’t do any of these things well.
And yet, because a lab result says “normal,” many women are told there’s nothing wrong. They’re not offered a deeper look. That’s what investigative blood analysis is for.
The Bottom Line
If you’re experiencing symptoms of iron deficiency and you’ve been told your bloods are normal, it’s worth getting a second opinion on those results. A number that falls within a reference range is not the same as a number that’s right for you.
Your symptoms matter. And sometimes, the most important thing a doctor can do is listen to them.
Dr Robyn Bradfield is the founder of Bloodfields, a virtual investigative blood analysis practice. If you’d like your blood results reviewed with the depth and context they deserve, you can book through our website.