Your Blood Test Came Back Normal. So Why Do You Still Feel Exhausted?
Prof. Vernon Louw has spent decades asking that question on behalf of his patients and his own family. Here’s what he wants you to know.
- A normal hemoglobin result does not rule out iron deficiency, ferritin testing is essential
- Iron deficiency without anemia causes fatigue, brain fog, low mood, palpitations and more
- At least 1 in 3 people globally are iron deficient, over 1 in 2 women in South Africa
- Maternal iron deficiency affects a child's brain development for 20+ years
- WHO (2025) and FIGO both now call for ferritin testing as standard
You went to the doctor. You described the fatigue, the brain fog, the low mood, the headaches that won’t shift. They ran a blood test. And they told you everything looked fine.
But everything doesn’t feel fine.
If that experience sounds familiar, you are not imagining it. And you are not alone. According to Professor Vernon Louw, one of the world’s leading clinical hematologists and a specialist in iron metabolism, what you may be experiencing is iron deficiency without anemia – and there is a critical difference between the two that most people, and many doctors, have never been taught.
"Many people have conflated anaemia or haemoglobin with iron deficiency. They think if a patients haemoglobin is normal, they can't have a problem - even if the iron levels are low."
Prof. Vernon Louw, Professor of Medicine, Stellenbosch University, South Africa
Who is Professor Vernon Louw?
Vernon Louw is Professor of Medicine and Executive Head of the Department of Medicine at Stellenbosch University in Cape Town, South Africa. He is a clinical hematologist with a specialisation in iron — iron deficiency, iron overload, iron metabolism, and the role of iron in women’s health. He also holds a PhD in transfusion medicine, which gives him a perspective on blood health that spans both the clinical and the systemic.
But his interest in iron didn’t begin in a laboratory. It began at home.
A personal connection to blood health
When Vernon was a child, his mother suffered a uterine rupture during childbirth and required 30 units of blood to survive. At the time, the risks of blood transfusion were not fully understood — hepatitis C had not yet been identified as a transmissible disease. His mother contracted it from that transfusion, and only discovered years later. That experience planted a quiet but lasting question in Vernon’s mind: when is a blood transfusion truly necessary, and when are there better alternatives?
Decades later, he found the answer in a concept called Patient Blood Management — optimizing a patient’s own blood health before, during, and after medical procedures, reducing the need for transfusion and improving outcomes. It would become central to his career.
The personal thread didn’t stop there. His wife and three daughters all live with iron deficiency. His oldest daughter, now also a doctor, experienced the transformation that comes with proper diagnosis and treatment firsthand — and has since joined him in developing an iron education programme. Iron deficiency, for Vernon Louw, has never been an abstract clinical problem. It is something he has watched affect the people he loves most.
Iron deficiency is the most common nutritional deficiency in the world. At least 1 in 3 people globally — and more than 1 in 2 women in South Africa — are estimated to be iron deficient. Many have no idea.
The problem with “your hemoglobin is fine”
If you have ever left a doctor’s appointment feeling dismissed, this section is for you.
The standard blood test most people receive checks hemoglobin — the protein in red blood cells that carries oxygen around the body. For decades, a normal hemoglobin result was considered reassurance that iron levels were adequate. It is not.
What iron actually does
Iron does far more in the human body than produce red blood cells. It is essential to the function of every single cell — including those responsible for energy production, cognitive function, mood regulation, temperature regulation, and immune response. When iron is low, the body’s cells cannot produce adequate ATP, the primary energy molecule that powers virtually everything we do.
Prof. Louw explains it this way:
"If your iron is low, your cells can't make energy — and you're actually running your body on low power mode. Like your phone at 5%. For people with iron deficiency, even if they are not anaemic, they're basically running on low power mode all the time. All the functions are not there."
Prof. Vernon Louw, Professor of Medicine, Stellenbosch University, South Africa
When symptoms become invisible
The symptoms of iron deficiency without anemia are wide-ranging and frequently dismissed as stress, anxiety, or simply the demands of modern life. They include persistent fatigue, irritability, brain fog, low mood, depression, palpitations, and headaches. Individually, each might seem minor. Together, and sustained over months or years, they represent a significant and treatable burden on quality of life.
The test that matters — and that is still not routinely ordered in many clinical settings — is a ferritin test. Ferritin measures the body’s iron stores, not just what is circulating in the blood. A person can have a normal hemoglobin and critically low ferritin. Without testing ferritin, iron deficiency can go undetected for years.
The burden women carry
Iron deficiency disproportionately affects women — and the reasons are both biological and systemic.
Menstruation, pregnancy, and the postpartum period all place significant demands on iron stores. Heavy menstrual bleeding is one of the most common and most overlooked causes of iron deficiency. Prof. Louw notes that in high-income countries, around half of people who experience heavy menstrual bleeding never discuss it with a doctor — because they have been told, or come to believe, that it is simply normal.
It is not normal. And the consequences of leaving it unaddressed extend beyond the individual.
"We know from actual data that doctors don't take women's complaints seriously. They normalise it. They make them feel as if you should just accept it. That's the way life is. That's not the way life is supposed to be - and it doesn't have to be that way."
Prof. Vernon Louw, Professor of Medicine, Stellenbosch University, South Africa
The intergenerational dimension of this is particularly striking. Iron deficiency during pregnancy affects the long-term neurological development of the baby — with research now suggesting that developmental delays linked to maternal iron deficiency can persist for 20 years or more. Even after birth, if a mother’s iron deficiency is left untreated, her infant’s developmental trajectory can fall measurably behind that of children whose mothers received treatment.
For Prof. Louw, this is not a peripheral concern. It is the reason early recognition matters so profoundly.
Research suggests that iron deficiency in pregnancy can affect a child's brain development for 20 years or more — even when the mother's iron deficiency is treated after birth rather than during pregnancy.
What the global evidence now says
The case for taking iron deficiency seriously is no longer a matter of emerging research. It is established clinical consensus — and it is now reflected in global health policy.
The World Health Organization published its Patient Blood Management Implementation Guidance in 2025, calling on every country to adopt national frameworks for optimising patients’ own blood health. The document explicitly addresses the importance of iron management as a cornerstone of that approach, and draws on the evidence base that specialists like Prof. Louw have spent careers building.
What FIGO says about iron testing
The World Federation of Gynaecology and Obstetrics (FIGO) has also published clear clinical guidance stating that haemoglobin testing alone is insufficient. FIGO’s position affirms that iron testing — including ferritin — must be part of standard assessment, and that the underlying cause of iron deficiency must always be identified and addressed. This guidance exists in accessible, printable formats that patients can bring to appointments.
These are not fringe positions. They represent the direction of travel of international clinical consensus — and they give patients a firm foundation for asking their doctor to go further than a standard blood count.
Talking to your doctor about iron
Knowing something is wrong and being able to advocate for yourself in a clinical setting are two different skills. Prof. Louw is practical and direct on this point.
He recommends going into an appointment prepared — with a trusted source, whether that is the FIGO guidance, a published article, or information from a credible health organization — and framing the conversation collaboratively rather than confrontationally. Something as straightforward as:
“I’ve been reading about iron deficiency and I’d really appreciate it if we could test my ferritin levels alongside my haemoglobin — I want to make sure we’re not missing anything.”
Positions the doctor as a partner rather than an adversary, and makes it easy for them to say yes.
He is also honest about the system’s limitations. Many GPs have not received comprehensive training in iron deficiency beyond its relationship to anemia. This is not a failure of individuals — it is a gap in medical education that specialists like Prof. Louw are actively working to close. If you have the option to seek out a GP with a specific interest in iron or women’s health, it is worth doing.
"Every person who has iron deficiency needs to insist on knowing why. They must always ask their doctor — why do I have this? It is not normal to just be iron deficient. There is always a cause."
Prof. Vernon Louw, Professor of Medicine, Stellenbosch University, South Africa
A message to clinicians
Prof. Louw reserves some of his most direct words for his own profession.
He has observed throughout his career that female doctors are among those most frequently affected by undiagnosed iron deficiency — and that treating their own deficiency often transforms their approach to patients. In his experience, one in two to one in three female doctors who test their own iron discover they are deficient. Once treated, they describe the change as significant. And they become, almost universally, more open to recognising and treating iron deficiency in their patients.
His challenge to clinicians is framed not as criticism but as conscience:
"Once you've got this knowledge, you need to ask yourself — would I accept avoidable anaemia or the risks of blood transfusion for myself, my family? Or will I just tolerate it for my patients? What we want for ourselves and our families is what we must want for our patients as well."
Prof. Vernon Louw, Professor of Medicine, Stellenbosch University, South Africa
It is a question that cuts through clinical distance. And it is one that Patient Blood Management — the discipline that first brought Prof. Louw into this space — was built to answer.
Where to go from here
If you recognize your own experience in this blog, the most important next step is to ask for a ferritin test. A hemoglobin result alone is not enough. If your ferritin is low — even if your hemoglobin is normal — that is a finding that warrants attention and, importantly, investigation into the underlying cause.
You can also explore the resources below to learn more.
Questions to Ask About Your Blood Health
- Can we test my ferritin alongside my hemoglobin?
- If my ferritin is low, what could be causing it?
- Is heavy menstrual bleeding something we should investigate further?
- What are the treatment options if my iron is low?
- How long should I expect to take iron supplements, and how will we monitor progress?
Are you getting the right blood tests?
Disclaimer:
This information is educational, not medical advice. Always talk to your doctor before making changes to your health care.