From the Guidelines
No, a Complete Blood Count (CBC) does not include a bilirubin level. According to the guidelines on the management of abnormal liver blood tests 1, a full blood count, which is another term for a CBC, is recommended as part of the initial investigation for potential liver disease, but it does not include bilirubin. The initial investigation should include bilirubin, albumin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and γ-glutamyltransferase (GGT), in addition to a full blood count.
Key Points to Consider
- A CBC typically measures components of the blood including red blood cells, white blood cells, platelets, hemoglobin, and hematocrit.
- Bilirubin is measured separately as part of a liver function test panel or comprehensive metabolic panel.
- If you need to assess bilirubin levels, you should specifically request a liver function test or a comprehensive metabolic panel in addition to the CBC.
- Elevated bilirubin levels can indicate liver dysfunction, bile duct obstruction, or increased red blood cell destruction, which are distinct physiological processes that require separate testing from the cellular components evaluated in a CBC.
Clinical Implications
The guidelines emphasize the importance of interpreting abnormal liver blood test results in the context of the patient's past medical history and current medical condition 1. Therefore, it is crucial to order the appropriate tests, including a liver function test or comprehensive metabolic panel, in addition to a CBC, to ensure accurate diagnosis and management of liver disease.
From the Research
Complete Blood Count (CBC) and Bilirubin Level
- A Complete Blood Count (CBC) is a blood test that measures various components of the blood, including red and white blood cell counts, hemoglobin, and platelet count.
- However, a CBC does not typically include a bilirubin level test 2.
- Bilirubin level tests are usually part of a liver function test or a comprehensive metabolic panel, which includes assays for bilirubin (total and fractionated), among other tests 2.
Laboratory Evaluation for Jaundice
- Initial laboratory evaluation for jaundice should include assays for bilirubin (total and fractionated), as well as other tests such as a complete blood cell count, aspartate transaminase, alanine transaminase, gamma-glutamyltransferase, alkaline phosphatase, albumin, prothrombin time, and international normalized ratio 2.
- Measuring fractionated bilirubin allows for determination of whether the hyperbilirubinemia is conjugated or unconjugated 2.
Diagnosis and Evaluation of Hyperbilirubinemia
- The diagnosis and evaluation of hyperbilirubinemia involve a careful history and physical examination, followed by directed imaging of the biliary tree and liver 3.
- Elevated levels of bilirubin almost always indicate the presence of an underlying disease state, and the best approach to evaluating a patient with jaundice is to start with a careful history and physical examination, followed by imaging assessment of the biliary tree and liver 3.