Complete Blood Count (CBC)
A comprehensive blood test that measures red blood cells, white blood cells, and platelets to assess overall health, detect infections, and screen for blood disorders like anemia.
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What this test measures
A Complete Blood Count (CBC) is a blood test that measures amounts and sizes of red blood cells, white blood cells, and platelets in the blood. Healthcare providers can use it to monitor and diagnose medical conditions and check on the health of the immune system. This comprehensive test provides valuable insights into several key components of the blood that are essential for proper body function.
The CBC indicates the counts of white blood cells, red blood cells and platelets, the concentration of hemoglobin, and the hematocrit (the volume percentage of red blood cells). The red blood cell indices, which indicate the average size and hemoglobin content of red blood cells, are also reported, and a white blood cell differential, which counts the different types of white blood cells, may be included. Infections, medications, anemia and cancer can cause abnormal results. The test is often performed as part of routine health assessments or when individuals experience symptoms like fatigue, weakness, fever, or unusual bruising that may indicate underlying blood disorders or infections.
What's included
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing persistent fatigue, weakness, or unexplained tiredness that may indicate anemia or other blood disorders
- Those with symptoms of infection such as fever, chills, or swollen lymph nodes that warrant immune system evaluation
- People with unusual bleeding, frequent bruising, or prolonged bleeding that could suggest platelet or clotting abnormalities
- Individuals undergoing routine health screenings or annual physical examinations as part of preventive healthcare
- Those with chronic medical conditions requiring ongoing monitoring of blood cell counts and overall health status
- People taking medications that may affect blood cell production or function, requiring regular monitoring for side effects
What to expect
Preparation
No special preparation is typically required for a CBC test. Patients can eat and drink normally before the test unless other blood tests requiring fasting are being performed simultaneously. Individuals should inform their healthcare provider about all medications and supplements they are taking, as some may affect test results.
Sample Type
Blood sample collected through a simple blood draw from a vein in the arm
Collection
A nurse or lab technician will take a sample of blood by putting a needle into a vein in the arm. The procedure takes just a few minutes and involves minimal discomfort. A CBC is a safe, common test with very low risk of complications.
Turnaround
Results are typically available within 24-48 hours after the blood sample is collected and sent to the laboratory for analysis
Understanding your results
The results are interpreted by comparing them to reference ranges, which vary with sex and age. Not all results falling outside of the reference range require medical intervention. Healthcare providers evaluate CBC results in the context of symptoms, medical history, and other clinical findings to determine if any abnormalities are significant and require further investigation or treatment.
Each lab has a different range for what's normal, and the normal range is just a guide. A value that isn't in the normal range may still be normal for the individual. Trends over time are often more meaningful than single test results, and providers may recommend repeat testing if results are outside normal ranges to confirm findings.
| Population | Reference Range | Notes |
|---|---|---|
| Adult Males | RBC: 4.5-5.9 million cells/mcL, Hemoglobin: 13-18 g/dL, Hematocrit: 41.5-50.4%, WBC: 4,000-11,000 cells/mcL, Platelets: 150,000-400,000/mcL | Reference ranges for healthy adult males based on typical laboratory standards |
| Adult Females | RBC: 4.1-5.1 million cells/mcL, Hemoglobin: 12-16 g/dL, Hematocrit: 35.9-44.6%, WBC: 4,000-11,000 cells/mcL, Platelets: 150,000-400,000/mcL | Reference ranges for healthy adult females, with slightly lower red cell values due to physiological differences |
| Children | Varies significantly by age | Pediatric reference ranges differ from adult values and change throughout childhood development |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
Low red blood cell counts (anemia) may be caused by nutritional deficiencies (like B12 deficiency or iron deficiency), blood loss/bleeding, low kidney function and blood and bone marrow disorders. Low white blood counts may be caused by autoimmune diseases, medications, bone marrow disorders and infections. Low platelet counts may be caused by immune thrombocytopenia, certain cancers and hemolytic uremic syndrome. Diet, activity level, medicines, having a menstrual period, not drinking enough water, and other factors can affect the results. If any levels are abnormal, it doesn't always mean there is a medical condition that needs treatment. Low results may be temporary and resolve on their own, particularly if they are only slightly below normal ranges or are related to recent illness or lifestyle factors.
What does a “High” result mean?
High white blood counts may be caused by infections, allergic conditions, autoimmune conditions, lymphoma and leukemia. Elevated red blood cell counts, hemoglobin, or hematocrit may indicate dehydration, lung disease, or in rare cases, blood disorders like polycythemia. High platelet counts may be caused by infections and immune system issues. High platelet count (thrombocytosis) is defined as more than 450,000 platelets per microliter. Elevated results don't always indicate serious conditions and may be temporary responses to illness, stress, or other factors. It's important to note that high values can sometimes be related to lifestyle factors, medications, or temporary conditions. Healthcare providers typically recommend additional testing or monitoring when results are significantly elevated to determine the underlying cause and appropriate next steps.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. At LevelPanel, patient privacy and confidentiality are our highest priorities. All CBC test results are handled with strict confidentiality protocols and are <u>not reported to your doctor</u> unless you specifically choose to share them. Your test results are <u>not part of your medical records</u> and will not appear in your permanent healthcare file without your explicit consent. Your CBC test results are also <u>not on insurance statements</u> or Explanation of Benefits (EOB) forms, ensuring complete privacy from insurance companies and employers. We use secure, HIPAA-compliant systems to protect your personal health information, and only you have access to your results through our secure patient portal. No doctor visit required to order this test, giving you complete control over your health information and testing decisions. We never share your test results with third parties, employers, or government agencies without your written authorization. Your privacy is protected by federal law, and we go above and beyond these requirements to ensure your health information remains completely confidential and under your control.
Frequently asked questions
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CPT Code: 85025
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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Not sure if this is the right test? Contact our care team for guidance.