Lab Medicine Edition | CBC: Hemoglobin/Anemia (Micro, Macro, Hemolytic)
Apr 25, 2024
auto_awesome
Renowned Mayo Clinic Hematologist, Dr. Ronald S. Go, discusses evaluating abnormalities in hemoglobin levels, different types of anemia, and the importance of clinical context and confirmatory testing. Topics include non-heme causes of polycythemia, diagnostic approach for polycythemia vera, differential diagnosis and workup for anemia, diagnostic value of Mean Corpuscular Volume in anemias, and guidance on anemia testing and hemoglobin interpretation.
Providers should consider repeating CBC for unexpectedly elevated hemoglobin levels to rule out blood disorders.
Understanding the three main causes of anemia - blood loss, decreased production, and hemolysis - is crucial for effective diagnostic workup.
Deep dives
Understanding Elevated Hemoglobin in Outpatient Care
In outpatient settings, a key consideration for providers is the context of an elevated hemoglobin. If hemoglobin levels are above normal unexpectedly, repeating the CBC to confirm accuracy is advised. Consistent elevation may prompt further evaluation to determine if it indicates a blood disorder. The differential diagnosis of elevated hemoglobin includes common causes like dehydration, hypoxemia, medication side effects, and less frequently, hereditary conditions.
Evaluation of Anemia: Blood Loss, Production, and Hemolysis
When facing a patient with anemia, understanding the three main causes – blood loss, decreased production, and hemolysis – is crucial. An initial assessment focuses on differentiating these factors to guide the diagnostic workup effectively. Identifying the underlying cause involves considering the clinical history, implications of microcytic anemia, and targeted lab tests to rule out common etiologies such as iron deficiency, B12 deficiency, and other hematologic disorders.
Significance of MCV in Anemia Diagnosis
The Mean Corpuscular Volume (MCV) plays a significant role in narrowing down the potential causes of anemia. While microcytic anemia often raises suspicion of certain deficiencies like iron or B12, interpreting MCV values in context with hemoglobin levels can aid in pinpointing specific conditions like thalassemia. Understanding the relationship between MCV, hemoglobin, and their gaps can provide valuable insights into the etiology of microcytic anemia.
Optimizing Referrals for Hematologic Consultations
Efficient referrals for hematologic consultations can be enhanced by considering pre-test probabilities and the predominant causes of anemia – blood loss, decreased production, and hemolysis. Highlighting common triggers for iron deficiency like frequent blood donation can streamline diagnostic pathways. Employing strategic repeat testing and thorough patient history assessments can help minimize unnecessary investigations and ensure appropriate management strategies are employed.
Join our host, Andy J. Herber, P.A.-C., as he discusses the complete blood count (CBC), which is one of the most ordered laboratory tests in the primary care setting. Providers are frequently tasked with evaluating all aspects of the CBC. A keen understanding of this laboratory test is essential to providing quality care for patients. Joining the first episode of this series is renown Mayo Clinic Hematologist, Ronald S. Go, M.D., who will be discussing evaluating abnormalities, hemoglobin and differing types of anemia.