Components of a Full Blood Count

Components of a Full Blood Count

Blood contains different components that do different things. These include transporting oxygen around the body, responding to infections, and wound healing. A full blood count is a test to examine the different components of your blood. This article covers the general components of a full blood count and some information about which components are specifically relevant to gender affirming hormone treatment.

Components of a full blood count

Red blood cells

Red blood cells carry oxygen around the body. The following components of the full blood count pertain to red blood cells.
  1. Haemoglobin — This measures the component of red blood cells that carries oxygen.
  2. Haematocrit — This measures the volume percentage of red blood cells in the blood, which roughly reflects the thickness of the blood.
  3. Red cell count — This measures the number of red blood cells in a given amount of blood.

Platelets

Platelets are the components of blood that are involved in clotting in response to injury.
  1. Platelet count — This measures the number of platelets in a given amount of blood.

White blood cells

White blood cells are involved in the body's response to infections. There are different sorts of white blood cells which do different things. These include lymphocytes, monocytes, neutrophils, eosinophils, and basophils. The following components of the full blood count pertain to white blood cells.
  1. White cell count — This measures the total number of white blood cells in a given amount of blood.
  2. Lymphocytes — This measures a certain sort of white blood cell which is usually involved in responses to viral infections.
  3. Monocytes — This measures a certain sort of white blood cell which is usually involved in responses to bacterial infections.
  4. Neutrophils — This measures a certain sort of white blood cell which is usually involved in responses to bacterial infections.
  5. Eosinophils — This measures a certain sort of white blood cell which is usually involved in responses to parasitic infections and allergies.
  6. Basophils — This measures a certain sort of white blood cell which is usually involved in responses to allergies.

Relevance to gender affirming hormone treatment

A full blood count can be useful to screen for various health conditions, including anaemia, infections, and clotting disorders. Some of the components are more directly relevant than others to gender affirming medical treatment. These include the following.

Haematocrit

Testosterone increases the production of red blood cells by the body, which can increase the thickness of the blood. This accounts for why cis men tend to have a higher haematocrit than cis women. Accordingly, exogenous testosterone in masculinising hormone treatment can be associated with increased haematocrit. n the majority of cases, masculinising hormone treatment in trans men increases the haematocrit to levels usually considered healthy in cis men. 

Sometimes, however, masculinising hormone treatment in trans men can thicken the blood further, so that the haematocrit rises above the levels usually considered healthy in cis men. Erythrocytosis is a potential concern because it may be associated with an increased risk of blood clots, heart attacks, and strokes. For this reason, it is recommended that people who are taking testosterone have blood tests to check their haematocrit regularly.

Haemoglobin

Testosterone increases the production of red blood cells by the body, which can increase the level of haemoglobin in the blood. Along with haematocrit, a high concentration of haemoglobin can indicate thickening of the blood due to erythrocytosis. As noted above, erythrocytosis is a potential concern because it may be associated with an increased risk of blood clots, heart attacks, and strokes. For this reason, it is recommended that people who are taking testosterone have blood tests to check their haemoglobin regularly.



Order Your At-Home Finger Prick Test Through the GenderGP Blood Test Portal Now (Available for Members and Non-Members)
Note: To use the finger prick test, you need to be 16 or older and not taking spironolactone. Vitall, the service provider, will send your blood test results directly to your email address.

If you're taking spironolactone, you'll need an intravenous blood sample. You can get this through an online blood test service of your choosing, through your GP if they're willing to help, or at a private clinic/hospital.

If you need a Blood Test Referral Letter to advise your GP or healthcare provider, you can purchase one through the Treatment Recommendation form for £20. The letter explains why you need blood tests and which ones you'll need to get (read more here: Obtaining Letters and Reports).

When you have your results, please submit them in the Treatment Recommendation form for analysis.

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