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Can Having Hashimotos Affect Your Blood Cell Count

Learn how low thyroid hormone levels affect your CBC – complete blood counts.
Can Having Hashimotos Affect Your Blood Cell Count
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Hashimoto’s is a thyroid autoimmune disorder that occurs when your immune system attacks and destroys your thyroid cells. Because of this, your thyroid gland becomes underproductive, resulting in low thyroid hormone levels, a condition called hypothyroidism. In fact, Hashimoto’s is the primary cause of hypothyroidism.

Hashimoto’s is commonly associated with symptoms like weight gain, fatigue, or cold intolerance. But Hashimoto’s can also cause symptoms you may be unfamiliar with, such as changes in your blood cell counts.

About 50% of those with a thyroid disorder have an abnormal blood cell count, also known as a complete blood count or CBC. This article explores the link between thyroid hormone levels and your blood cell count.

Free T3

Free T3 is a hormone produced by the thyroid gland. Levels of this fluctuate when individuals have an under or overactive thyroid gland.


Thyroid-stimulating hormone, TSH, is the hormone responsible for controlling hormone production by the thyroid gland. The hormone TSH is considered the most sensitive marker for screening for thyroid diseases and conditions. Our thyroid panel is ideal for TSH testing at home and will tell you how your levels compare to normal TSH levels.

TPO Antibodies

Thyroid peroxidase antibodies are antibodies that can bind to thyroid enzymes, suppressing thyroid function. They are elevated in a condition called Hashimoto's disease, which is the most common type of hypothyroidism in the USA.

Free T4

Free T4 is the predominant hormone produced by the thyroid gland. Levels fluctuate when individuals have an under or overactive thyroid gland. Testing your free T4 with this thyroid function test lets you see if your thyroid hormone production is at a normal level.

Reverse T3


RT3 is a metabolite of T4. Typically, when T4 loses an atom of iodine—a process known as monodeiodination—it becomes (T3), the active thyroid hormone.The body also converts T4 into rT3, which is an inactive form of T3 that is incapable of the metabolic activity that is normally carried out by T3.

Vitamin D


Some observational studies have found low blood levels of vitamin D in patients with hypothyroidism and Hashimoto’s as well as hyperthyroidism due to Gravesʼ disease. It is not clear from these studies if low vitamin D is a cause, a consequence or an innocent bystander in the development of these common thyroid conditions.

What is a blood count?

A blood count is a standard blood test that provides your healthcare provider with information about the cells in your blood.

Your blood contains three main types of cells, each with a unique function:

  • Red blood cells (RBC) carry oxygen from the lungs to the rest of your body.
  • White blood cells (WBC) fight off infections and other diseases.
  • Platelets help stop bleeding by forming a blood clot.

Any of these counts can be further analyzed by conducting additional lab tests. For instance, if your red blood cell count is low, your healthcare provider may also look at the following to better understand why these levels are outside the normal range: i

  • Hemoglobin is a specific protein in your RBCs.
  • Hematocrit is the volume of blood that makes up your RBCs.
  • Mean corpuscular volume is the average size of your RBCs.

The link between Hashimoto’s and abnormal blood count

Thyroid disorders - both hypothyroidism and hyperthyroidism (high thyroid hormone levels) - can impact any of your blood cells. Why is this?

For those with hypothyroidism, a lack of thyroid hormone causes three things to happen:

  1. Your bone marrow can’t make enough hemoglobin and other red blood cell precursors to meet your body’s demands, affecting the formation of red blood cells.
  2. Erythropoietin levels decrease, slowing the formation of new red blood cells.
  3. Your tissues may not get enough oxygen resulting in symptoms of anemia.

Substantial evidence supports the link between low red blood cell and hemoglobin levels in those with Hashimoto’s or hypothyroidism. A 2020 study showed that 50% of hypothyroidism patients had low hemoglobin. But, the link between Hashimoto’s and abnormal platelets or white blood cell counts is less clear.

That same 2020 study showed abnormalities in red blood cells, hemoglobin, and white blood cells were common in those with a thyroid disorder. About 5% of hypothyroidism patients in this study had white blood cell levels above the reference range. Platelet counts were not affected in this study, which differs from other studies.

Hashimoto’s and anemia

Those with hypothyroidism commonly have decreased red blood cells or hemoglobin, a medical condition called anemia. And since red blood cells play a crucial role in carrying oxygen throughout your body, a lack of these cells can result in symptoms of anemia, including:

  • Appearing pale
  • Chills
  • Dizziness
  • Headaches
  • Shortness of breath
  • Tiredness
  • Weakness

Symptoms of anemia may develop slowly, depending on your degree of anemia. As you might be able to tell, some of the symptoms overlap with those commonly seen in individuals with autoimmune thyroid disease like Hashimoto’s.

Over 40% of individuals with overt hypothyroidism were found to have anemia, according to a 2017 study. People with Hashimoto’s develop anemia for several reasons. First is low thyroid hormone levels. A deficiency in thyroid hormones reduces hemoglobin formation in your bone marrow, ultimately decreasing red blood cells. The second is iron deficiency.

While iron deficiency is the most common cause of anemia, a deficiency in folate and vitamin B12 can also cause anemia in those with autoimmune diseases like Hashimoto’s. Roughly 25% of anemia cases in those with a thyroid disorder are due to these two deficiencies.

Iron deficiency anemia

Iron is essential for producing thyroid hormones - T3 (triiodothyronine) and T4 (thyroxine). Your thyroid mainly produces T4, the inactive form. To affect your cells, thyroid hormone must convert T4 to T3, the active state. And iron is essential for making this conversion happen. A lack of iron would limit how much T4 can convert to T3.

Iron deficiency anemia is common in those with Hashimoto’s, especially at the time of diagnosis or when untreated. Over 40% of women with untreated hypothyroidism reported having iron deficiency anemia.

Symptoms of iron deficiency anemia are the same as other types of anemia. So, checking your blood level is the only way to tell if you are iron deficient.

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What is the treatment for abnormal blood counts?

Treatment for an abnormal blood count depends on the abnormal value and the underlying cause.

For instance, iron deficiency anemia is managed in several ways. If you have mild to moderate iron deficiency, your healthcare provider may recommend taking over-the-counter iron supplements or eating iron-rich foods. On the other hand, a severe iron deficiency may require intravenous (IV) iron infusions or even a blood transfusion.

If your abnormal blood counts are due to Hashimoto’s or other thyroid disorders, achieving a euthyroid state will help improve your blood counts. A euthyroid state, or when your body has an appropriate amount of thyroid hormone, is typically achieved by taking a thyroid hormone replacement medication.

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A note from Paloma Health

Healthcare providers are encouraged to check blood counts on a routine basis in patients with hypothyroidism, Hashimoto’s, and other thyroid disorders. If your blood counts have not been tested recently, ask your healthcare provider about it. Addressing underlying deficiencies, including mild ones, can make a difference in your thyroid function and relief of symptoms.

Whether it is addressing underlying nutrient deficiencies, changing your thyroid medication dose, or checking your thyroid function, Paloma Health has you covered. Here at Paloma, our team of expert thyroid providers and nutritionists deliver personalized treatment for hypothyroidism. The best part: this can all be done from the comfort of your home. Join our growing community today.


Ahmed SS, Mohammed AA. Effects of thyroid dysfunction on hematological parameters: Case controlled study. Ann Med Surg (Lond). 2020;57:52-55. doi:

National Library of Medicine. Complete Blood Count (CBC): MedlinePlus Lab Test Information. Medline Plus. Published 2017. Accessed July 12, 2023.

Dorgalaleh A, Mahmoodi M, Varmaghani B, Kiani Node F, Saeeidi Kia O, Alizadeh Sh, Tabibian Sh, Bamedi T, Momeni M, Abbasian S, Kashani Khatib Z. Effect of thyroid dysfunctions on blood cell count and red blood cell indice. Iran J Ped Hematol Oncol. 2013;3(2):73-7

Anemia - Symptoms | NHLBI, NIH. Last updated March 24, 2022. Accessed July 12, 2023.

Ashraf TS, De Sanctis V, Yassin M, Wagdy M, Soliman N. Chronic anemia and thyroid function. Acta Bio Medica : Atenei Parmensis. 2017;88(1):119-127. doi:

National Heart, Lung, and Blood Institute. Anemia - Iron-Deficiency Anemia | NHLBI, NIH. Published March 24, 2022. Accessed July 12, 2023.

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Emilie White, PharmD

Clinical Pharmacist and Medical Blogger

Emilie White, PharmD is a clinical pharmacist with over a decade of providing direct patient care to those hospitalized. She received her Doctor of Pharmacy degree from Massachusetts College of Pharmacy and Health Sciences. After graduation, Emilie completed a postgraduate pharmacy residency at Bon Secours Memorial Regional Medical Center in Virginia. Her background includes caring for critical care, internal medicine, and surgical patients.

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