From the Guidelines
Yes, you should offer a blood test to evaluate the patient's condition. Blood tests provide valuable objective data that can help establish a diagnosis, monitor disease progression, or evaluate treatment effectiveness. According to the most recent and highest quality study 1, blood tests, which may include a full blood count, kidney and liver function, C reactive protein, ferritin, B-type natriuretic peptide, and thyroid function, can help rule out serious or urgent complications, evaluate symptoms secondary to ongoing symptomatic COVID-19 or post-COVID-19 syndrome, or to look for new, unrelated diagnoses. Some key points to consider when offering a blood test include:
- The patient's presenting symptoms and medical history
- The potential risks and benefits of the test
- The timing of blood collection, as some tests require fasting (typically 8-12 hours), while others can be done at any time
- The interpretation of test results in the context of the patient's overall clinical picture, rather than in isolation. It's also important to note that while some studies suggest that routine laboratory testing may not be necessary for all patients 1, the most recent and highest quality study 1 recommends offering blood tests to evaluate the patient's condition.
From the Research
Evaluation of Patient Condition
To evaluate a patient's condition, offering a blood test can be a valuable diagnostic tool. The complete blood count (CBC) is one of the most frequently ordered laboratory tests in medicine, providing information about the production of all blood cells and identifying the patient's oxygen-carrying capacity 2.
Components of a Blood Test
A blood test, such as a CBC, includes various components, such as:
- Red blood cell count
- Hemoglobin
- Hematocrit
- Red blood cell indices
- Reticulocyte count
- White blood cell count and differential
- Platelet count 2 These components can help diagnose various conditions, including anemia, certain cancers, infection, acute hemorrhagic states, allergies, and immunodeficiencies 3.
Diagnostic Tool
The CBC can be a powerful diagnostic tool when used in conjunction with a good history and physical examination, as well as with additional components of the minimum database, which include a chemistry panel and urinalysis 4. It can also provide information about the immune system through the evaluation of the white blood cell count with differential 3.
Predictive Value
Recent studies have suggested that the risk of cancer, cardiovascular disease, arteriosclerosis, type 2 diabetes, and metabolic syndrome can be predicted using CBC components, such as white blood cell count, neutrophil-to-lymphocyte ratio, hemoglobin, and platelet count 5.
Considerations
However, it is essential to consider the appropriateness of repeat testing, as unnecessary testing can result in significant costs to healthcare without compromising patient care 6. Therefore, it is crucial to evaluate the patient's condition and medical history before offering a blood test.