Q. Can taking Iron pills a few days before ferritin test give false reading?

Answered by
Dr. Smrita Singh
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on Aug 17, 2018

Hello doctor,

I am a 22-year-old woman who is struggling with extreme fatigue, muscle weakness, tire easy or poor endurance, treatment-resistant depression, anxiety, panic disorder, skin picking issues, sensory processing disorder and ADHD. I have been a strict vegetarian for 12 years now and for a lot of that time, my diet was poor and mostly carbohydrate based.

I have suspected an iron deficiency for a very long time. I had a test for it a few years ago and my hemoglobin was normal but my ferritin was only 39. My doctor said it was fine. I recently had a terrible experience with several methods of birth control and for a few months was having 10 day periods twice a month, and at its worst, I was bleeding for a month straight. I started taking a food-based iron for 2 to 3 months (27 mg) and had my iron checked twice within six months. Both times my ferritin was up to around 80.

However, I still feel increasingly tired and other conditions are being ruled out. I just realized that before both of those tests with normal results, I had taken an iron pill within two days of the test.

My question is could that have given me a false reading on the ferritin test? If I would have had iron the day before? Is a couple months of food based on iron enough to have raised my levels that fast? And lastly, given the heavy bleeding and relative lack of dietary iron in my life, how could I not be iron deficient? Currently, I am taking Clonazepam PRN, Lamictal 50 mg.

Dr. Smrita Singh

Hematology Pathology


Welcome to icliniq.com.

Ferritin is an acute phase reactant. This means that apart from reflecting iron stores, it also reflects the inflammatory condition in the body. Taking Iron supplements just a few days before the blood test is not sufficient to raise your serum ferritin levels so quickly.

But if there is any inflammation going on in your body, your serum ferritin levels will be raised. It is thus very important to rule out any inflammatory condition before interpretation of serum ferritin levels.

Have you checked your vitamin D and vitamin B12 levels?

Deficiency in vitamin B12 & Vitamin D can also produce fatigue, weakness and neural disorders.

You should get your blood levels of these two vitamins checked and continue taking your Iron and Folic acid supplements.

I would suggest that you take the regular Iron and Folic acid supplements available in the form of pills along with a glass of orange juice or lemon water for better absorption.

For more information consult a hematologist online --> https://www.icliniq.com/ask-a-doctor-online/hematologist

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