Regular testing is a routine part of cancer care, helping your medical team monitor your body’s response to treatment. Among these, blood tests, particularly the Complete Blood Count (CBC) and chemistry panels, are vital. These tests can detect subtle changes in your blood that might signal potential issues before they become serious. By closely monitoring your blood test results, your doctor can proactively manage your care, preventing many cancer-related complications and treatment side effects.
This article will explain the importance of understanding your blood test results, focusing on the Complete Blood Count (CBC) and its key components like the Absolute Neutrophil Count (ANC), to empower you to be more informed about your health during cancer treatment.
Accessing and Understanding Your Lab Results
Many patients find it beneficial to request copies of their lab results and discuss them with their cancer care team. Different labs may use slightly different normal ranges for blood tests. Having your own copy allows you to see the specific normal ranges used by the lab that processed your blood and understand where your results fall within those ranges.
Recent legislation, like the Cures Act, aims to improve patient access to medical records, including lab results, clinical notes, and cost information. This means you might be able to view your lab results on a patient portal, sometimes at the same time as, or even before, your healthcare provider.
Seeing your results without immediate context can sometimes cause anxiety, especially if the results are unclear or appear abnormal. Proactive communication with your healthcare provider who ordered the tests is key. Consider asking the following questions beforehand:
- What types of results should I expect, where can I access them, and when will they likely be available?
- What constitutes a normal or abnormal result, and what could each mean for my health?
- How and when will you contact me to discuss my results in detail?
- Who should I contact if I see my results first and have concerns?
Complete Blood Count (CBC): Your Body’s Cell Snapshot
The Complete Blood Count (CBC) is the most frequent blood test conducted during cancer treatment. Blood is a complex mixture of water, proteins, nutrients, and living cells. A CBC provides your cancer care team with a detailed analysis of the cells in your blood, measuring three primary types:
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Platelets (Plts)
Each of these cell types has a distinct function, and all can be affected by cancer and its treatments. Understanding these components is crucial for monitoring your health.
Red Blood Cells (RBCs) and Anemia
Red blood cells (RBCs) are responsible for transporting oxygen to and removing carbon dioxide from the cells throughout your body. The typical normal range for RBCs is between 4.2 and 6.1 million cells per microliter of blood (mcL), with slight variations between women (4.2-5.4 million/mcL) and men (4.7-6.1 million/mcL).
A CBC provides several measurements related to red blood cells. Your lab report may include values for:
- Hemoglobin (Hgb): This is the iron-containing protein in RBCs that carries oxygen. The normal range is generally 12-18 grams per deciliter (g/dL).
- Hematocrit (Hct): This indicates the percentage of your blood volume made up of RBCs. The normal range is typically 37-52%.
When hemoglobin (Hgb) and hematocrit (Hct) levels fall below normal, it’s known as anemia. Anemia means your body isn’t efficiently delivering oxygen to your cells. This can lead to symptoms like a rapid heartbeat, fatigue, shortness of breath, and general weakness.
White Blood Cells (WBCs) and Neutropenia: Key to Infection Fight
White blood cells (WBCs) are your body’s defense against infection. There are various types of WBCs, each playing a specialized role in fighting infections.
The neutrophil is a particularly important type of WBC for infection control. Doctors closely monitor your Absolute Neutrophil Count (ANC), which reflects the number of neutrophils in your blood. A normal ANC range for a healthy adult is between 2,500 and 6,000.
The ANC is calculated by multiplying your total WBC count by the percentage of neutrophils present. For example, if your WBC count is 8,000 and neutrophils constitute 50% of your WBCs, your ANC would be 4,000 (8,000 x 0.50 = 4,000).
Neutropenia is diagnosed when the ANC drops below 1,000. Your doctor will be particularly vigilant if your ANC falls below 500, as this significantly increases the risk of infection.
While a low WBC count increases infection risk, a high WBC count can indicate that your body is actively fighting an infection.
Platelets (Plts) and Thrombocytopenia: Managing Bleeding Risks
Platelets (Plts) are essential for blood clotting and help control bleeding. When your platelet levels are low, you may bruise or bleed more easily. The risk of bleeding becomes significantly higher when platelet levels drop below 20,000.
Low platelet counts are referred to as thrombocytopenia by your healthcare team. Monitoring platelet levels is crucial to prevent and manage bleeding complications.
Chemistry Panel (Metabolic Profile): Assessing Organ Function
Another crucial blood test is the chemistry panel, also known as a metabolic profile or blood chemistry profile. This test analyzes a single blood sample to measure various substances, including:
- Fats (lipids)
- Proteins
- Sugar (glucose)
- Electrolytes (such as potassium, magnesium, sodium, and calcium)
- Enzymes
Chemistry panels provide insights into how well your organs are functioning. For instance, liver function studies assess your liver’s health, while other tests evaluate kidney function. The chemistry panel can also reveal other metabolic imbalances in your body.
Cancer treatments can sometimes disrupt your body’s blood chemistry, leading to issues like a decrease in potassium levels. Dehydration, which can be caused by nausea, vomiting, or diarrhea, can also affect your blood chemistry balance. Your doctor may order blood chemistry tests if they suspect any of these problems.
If the tests reveal low electrolyte levels, your doctor may recommend supplementation. If dehydration is detected, intravenous (IV) fluids might be necessary. Regular blood chemistry tests are essential because imbalances can often develop without noticeable symptoms until they become severe.
Understanding Normal Ranges in Your CBC and Chemistry Panel
Each laboratory establishes its own reference range for what it considers normal values in CBC and chemistry panel results. These normal ranges can vary slightly between labs, so it’s important to refer to the specific normal ranges provided on your lab report. Normal ranges can also be influenced by factors like age and sex. Typically, lab reports will display the normal ranges for each test alongside your results, indicating if your values are high or low.
Common Terms and Normal Values on a CBC Report
The table below summarizes common tests, units, and general normal values found on a CBC report. Remember that these ranges are approximate and may vary slightly between labs.
| Test | Units* | Normal Values# | Comments |
|---|---|---|---|
| WBC (White Blood Cells) | x 1000/mm3 | 5–10 | Number of infection-fighting cells |
| RBC (Red Blood Cells) | x 1,000,000/mm3 | 4.2–6.1 | Number of RBCs |
| Hgb (Hemoglobin) | g/dL | 12–18 | Measures oxygen and carbon dioxide carrying RBCs |
| Hct (Hematocrit) | % | 37–52 | Percentage of blood composed of RBCs |
| Plt (Platelets) | x 1,000/mm3 | 150–450 | Indicates bleeding risk |
*Note that results are often abbreviated in lab reports. For example, a WBC result of 6.2 might be shown instead of 6,200. “K” is sometimes used to represent thousands, and “M” for millions. /mm3 (cubic millimeter) is equivalent to µL (microliter). g represents grams, and dL deciliter.
These normal ranges are approximate and can vary slightly between laboratories.
Here’s an example of CBC test results for someone with anemia (low hemoglobin and hematocrit):
| Test | Result | Reference Range# | Alternative Notation |
|---|---|---|---|
| WBC (White Blood Cells) | 6.2 x 1000/mm3 | 5–10 | 6.2K/mm3 or 6,200/mm3, 6.2K/µL or 6,200/µL |
| RBC (Red Blood Cells) | 4.4 x 1,000,000/mm3 | 4.2–6.1 | 4.4M/mm3 or 4,400,000/mm3, 4.4M/µL or 4,400,000/µL |
| Hgb (Hemoglobin) | 9 g/dL (L) | 12–18 | |
| Hct (Hematocrit) | 28% (L) | 37–52 | |
| Plt (Platelets) | 178 x 1000/mm3 | 150–450 | 178K/mm3 or 178,000/mm3, 178K/µL or 178,000/µL |
These normal ranges are approximate and can vary slightly between laboratories.
Results outside the normal range may be flagged with an “(H)” for high or “(L)” for low, or highlighted in some way to draw attention to the abnormal value.
Obtaining a copy of your lab results empowers you to compare your values against the normal ranges, facilitating informed questions and a deeper understanding of your health status.
References:
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Department of Health and Human Services Office of the Secretary. 21st Century Cures Act: Interoperability, Information Blocking, and the ONC Health IT Certification Program. 2020. Accessed at https://www.govinfo.gov/content/pkg/FR-2020-05-01/pdf/2020-07419.pdf on October 18, 2021.
Last Revised: October 23, 2023
