Low blood count: Causes, management and treatment

Written by: Dr David Wrench
Published: | Updated: 03/04/2023
Edited by: Sophie Kennedy

low blood count can be behind symptoms of fatigue or low energy but may have more serious consequences, such as an elevated risk of infection or bleedingDr David Wrench, a leading consultant haematologist, gives an expert guide to the various effects a low blood count can have on the body. The leading specialist also sheds light on how the different types of low blood count are investigated, managed and treated.



What is a low blood count?


A low blood count relates to the cells in our blood, which fall into three categories; white cells (including five different types of white cells), red cells (which gives us haemoglobin) and platelets. A low blood count can apply to either the haemoglobin, the white cells, or indeed one of the five subtypes of cells, or the platelets being below the lower limit of our reference range. Patients with a low blood count of red cells can be described as being anaemic.


Our reference range is taken from where most patients are on a scale. However, it’s important to be cautious with this because a low blood count is not always abnormal and some people may have their own blood count which is normal for them despite it being lower than in most people.



What can cause a low blood count?


There are lots of causes of a low blood count, as there are different blood counts that can be low; red cells, white cells and platelets. Often, what we call a reactive process in the body or inflammation can lead to blood counts being low. A low blood count may also be caused by infectionmedicationsdrugs or toxins. Patients exposed to other medical conditions, particularly immune conditions, can also develop a low blood count.


Sometimes the bone marrow, the factory that makes the blood in adults dominantly, can malfunction and lead to a low blood count. This may be due to a primary disorder in the bone marrow or due to the influence of another factor on the bone marrow production apparatus. So, it may be a 'failure of the factory' in that the bone marrow doesn’t produce enough of the blood count or in other cases, the body can destroy blood counts through immune processes that don’t function as they should.


Additionally, when vitamin deficiencies are at play, there may not be enough of the ingredients required for the blood counts which can lead to lower than usual levels.



What are the symptoms of a low blood count?


The symptoms patients experience are specific to the type of blood count that is low. If the red cells are low, patients can feel tiredwashed out and lacking energyAnaemia also cause patients to become fatigued and in some cases, patients report being short of breath on exertion.


A low count of white cells can particularly increase a patient’s predisposition to infections, meaning they may have recurrentserious or unusual infections.


When platelets are low, patients may find that they are bruising very easily or spontaneously and also bleeding more easily or heavily than normal.



Is a low blood count serious?


low blood count can be serious but often is not. Occasionally, low blood counts can have serious consequences as, with low platelets for example, the patient may be at high risk of bleeding. Similarly, a very low haemoglobin count can make a person unwell with anaemia and a low count of white cells can put them at an elevated risk of contracting serious infections quickly.


Most of the time, however, low blood counts are only mild to moderate and can be managed very well so are not serious. Even in cases where the blood count is very low and potentially serious, we can usually find a cause behind the issue which we are able to treat. Also, even if there is no obvious cause, we are often able to manage the effects of very low blood counts.


Blood in test tubes being analysed for low blood count


Does a low blood count always require treatment?


Although a low blood count doesn’t always require treatment, often they do need some sort of treatmentmanagement or investigation. There are lots of different presentations of low blood counts that may need treatment or management but this is very dependent on our investigation for potential causes of those blood counts.


When treatment is required, we may give blood back to patients. If, for example, a patient has low red cells and they are anaemic, they might need a red cell blood transfusionBlood transfusions come from donors and I encourage everyone, if they are able, to consider blood donation to support this essential aspect of patient care. If the platelets are low, we can sometimes give a transfusion of platelets, which is another part of the blood taken from a blood donation. In this way, blood transfusions can act like replacements in patients with some types of low blood count.


We can also give injections to boost the white cell count and other types of treatment may be applied to the cause of the low blood counts. In some cases, this may relate to replacing missing iron if the patient has a deficiency. This can be treated with tablets, as can some vitamin deficiencies that can be behind low blood counts, such as vitamin B12 or folic acid. It’s important to investigate to find the causes of these deficiencies.



What lifestyle changes can patients with low blood counts make to help to improve their condition?


Similar to treatment, beneficial lifestyle changes depend very much on the type of low blood count present in the patient. For patients with very low counts of white cells, we often give advice and education to the patient to try and minimise the risk of infection, as this they have an elevated predisposition to this. If patients with a low white cell count have a temperature, feel unwell or have any symptoms which are suggestive of infection, they should have an immediate doctor review.


Patients who have a low platelet count have an elevated risk of bleeding and it’s important that they are aware of this, particularly if they are planning to visit the dentist, for example.


If the red cells are low, the lifestyle advice will often relate to whatever aspect is causing that anaemia, such as a dietary deficiency. Advice from your haematology team and having a good awareness of the individual implications of your low blood count can help you to manage it, along with treatment.




If you are concerned by issues related to low blood count and wish to book a consultation with Dr Wrench, you can do so by visiting his Top Doctors profile.

By Dr David Wrench

Dr David Wrench is a highly-experienced, London-based consultant haematologist with expertise in all areas of his field, particularly in the diagnosis and treatment of blood cancers and lymphoma. His range of specialist knowledge includes lymphomas, non-Hodgkin's lymphoma, Hodgkin's disease, low blood count, anaemia, and lymphadenopathy

After completing his studies in medicine at Cambridge University, Dr Wrench specialised in haematology and received his training at numerous esteemed London hospitals. He attends private patients at London Bridge Hospital and at Guy's and St Thomas' Private Healthcare. As well as this, he has worked within the NHS at the Guy's and St Thomas' NHS Foundation Trust since 2012. For patients with lumps, masses, or similar potentially-cancerous symptoms, Dr Wrench has led a rapid access diagnostic service.  

In addition to his clinical work, Dr Wrench holds prestigious positions within esteemed organisations. He is the clinical lead for Teenage and Young Adult (TYA) cancer at Guy’s and St Thomas’ private health care, co-chair of the SELCA haemato-oncology group, and governance lead for clinical haematology. Additionally, he is a member of both the NCRI low grade lymphoma group and of the Blood Cancer UK Healthcare advisory panel. 

During his PhD at Barts Cancer Institute, Dr Wrench published lead scientific papers in lymphoma. His research interests involve novel therapies and the aggressive transformation of lymphoma, as well as haematological malignancies and the rapid diagnosis of lumps. He is driven to improve both the treatment and outcome of patients with lymphoma.  

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