Understanding Side Effects of Breast Cancer Medicines: Blood Tests during Chemotherapy

Living with breast cancer involves navigating a complex landscape of treatments, medications, and potential side effects. As you embark on the journey of chemotherapy, it’s crucial to comprehend the various aspects of your treatment plan. One integral component that ensures the effectiveness and safety of your therapy is regular blood tests. In this article, we will delve into the importance of regular blood tests during chemotherapy, providing you with insights on interpreting results and understanding their significance.

Importance of Regular Blood Tests

Chemotherapy is a powerful weapon against cancer, but it also affects healthy cells in your body, including those in the bone marrow, which produces blood cells. Regular blood tests serve as a critical tool for monitoring the impact of chemotherapy on your blood counts. These counts include red blood cells (RBCs), white blood cells (WBCs), and platelets. Let’s explore why these blood components are so vital:

Red Blood Cells (RBCs)

  • Red blood cells are responsible for carrying oxygen from your lungs to the rest of your body.
  • Chemotherapy can suppress the bone marrow’s ability to produce RBCs, leading to anemia.
  • Anemia can cause fatigue, weakness, and shortness of breath.

White Blood Cells (WBCs)

  • White blood cells are the body’s defense against infections.
  • Chemotherapy may reduce WBC counts, making you more susceptible to infections.
  • Regular blood tests help your healthcare team assess your risk of infection and take preventive measures.


  • Platelets are crucial for blood clotting.
  • Chemotherapy can decrease platelet counts, leading to an increased risk of bleeding.
  • Monitoring platelet levels through blood tests helps prevent excessive bleeding.

Blood Tests during Chemotherapy

Understanding the frequency and purpose of blood tests during chemotherapy is key to managing your treatment effectively.

Frequency of Blood Tests

  • Your healthcare team will establish a schedule for blood tests based on your chemotherapy regimen.
  • Initially, tests may be more frequent to closely monitor your body’s response to treatment.
  • As your treatment progresses, the frequency may decrease, but regular monitoring remains essential.

Interpreting Blood Test Results

Interpreting blood test results can be overwhelming, but breaking it down can make it more manageable.

Red Blood Cell Count

  • Normal Range: 4.5 to 5.5 million cells/mcL
  • Below Normal: Indicates anemia, potentially requiring adjustments to your treatment plan.
  • Above Normal: Rare but may signal a reaction to certain medications.

White Blood Cell Count

  • Normal Range: 4,000 to 11,000 cells/mcL
  • Below Normal: Increases infection risk; your healthcare team may recommend precautions.
  • Above Normal: Could be a reaction to medications or an indication of an underlying issue.

Platelet Count

  • Normal Range: 150,000 to 450,000 platelets/mcL
  • Below Normal: Increased risk of bleeding; precautions may be necessary.
  • Above Normal: May result from certain medications or conditions.

Coping with Blood Test Results

Receiving blood test results can evoke a range of emotions. It’s essential to understand that fluctuations in your blood counts are a normal part of the chemotherapy journey. However, proactive measures can help manage these changes effectively.

Nutritional Support

  • A well-balanced diet rich in iron, vitamins, and nutrients can support blood cell production.
  • Consult your healthcare team for dietary recommendations tailored to your needs.

Medication Adjustments

  • If blood counts deviate significantly from the normal range, your healthcare team may adjust your chemotherapy dosage or schedule.
  • This ensures that your treatment remains effective while minimizing side effects.

Infection Prevention

  • Taking precautions to prevent infections is crucial, especially if your WBC count is low.
  • Practice good hygiene, avoid crowded places, and inform your healthcare team promptly if you notice signs of infection.

Communicating with Your Healthcare Team

Maintaining open communication with your healthcare team is paramount throughout your chemotherapy journey. Your experiences and any symptoms you encounter provide valuable insights for your medical professionals to tailor your treatment plan effectively.

Questions to Ask Your Healthcare Team

  1. What do my current blood test results indicate about my treatment?
  2. Are there any adjustments needed in my chemotherapy plan based on these results?
  3. How can I manage side effects related to changes in my blood counts?


In the realm of breast cancer treatment, understanding the nuances of chemotherapy, especially the role of blood tests, empowers you to actively participate in your care. Regular blood tests are not just numbers on a report; they are windows into the effectiveness and impact of your treatment on your body. By staying informed, engaging with your healthcare team, and taking proactive steps, you can navigate the challenges of chemotherapy with resilience and confidence. Remember, each blood test is a step closer to overcoming breast cancer and reclaiming your health.