What is the interpretation of the patient's complete blood count (CBC) results, which show leukocytosis, erythrocytosis, hyperhemoglobinemia, hyperhematocritemia, and thrombocytosis, with abnormal differential counts, including neutrophilia, lymphopenia, and monocytosis?

From the Guidelines

The recent lab results indicate an elevated red blood cell count, hemoglobin, and hematocrit, suggesting polycythemia or erythrocytosis, which requires immediate medical attention to rule out underlying conditions such as dehydration, high altitude, smoking, lung conditions, or bone marrow disorders. The current values are: red blood cell count (5.70), hemoglobin (16.0), and hematocrit (49.2%), all of which are above the reference range. These findings are crucial as they may indicate an increased risk of clotting due to thickened blood. The white blood cell count is currently within the normal range, but it was elevated 11 years ago, and the platelets are normal now but were slightly low in the past. The differential shows a normal distribution of white blood cell types in the recent test. Key points to consider include:

• Elevated red blood cell parameters
• Normal white blood cell count currently, but elevated in the past
• Normal platelet count currently, but slightly low in the past
• Normal differential of white blood cell types Given the potential risks associated with polycythemia or erythrocytosis, it is essential to schedule an appointment with a healthcare provider to discuss these findings and determine the appropriate course of action, which may include additional testing such as arterial oxygen levels, erythropoietin levels, or possibly bone marrow evaluation, as suggested by guidelines for the diagnosis and management of myeloproliferative neoplasms 1. Staying well-hydrated and avoiding tobacco products would be prudent while awaiting medical evaluation. A comprehensive metabolic panel, complete blood count with differential, erythrocyte sedimentation rate, C-reactive protein, and quantitative immunoglobulin levels should also be considered, as recommended for the diagnosis and clinical management of certain hematological conditions 1.

From the Research

Hematological Parameters

• The patient's hematocrit (Hct) level is 49.2%, which is above the reference range of 34.8-45.8% 2.
• The patient's hemoglobin (Hb) level is 16.0 g/dL, which is above the reference range of 11.7-15.7 g/dL 2.
• The patient's red blood cell (RBC) count is 5.70 x10E6/uL, which is above the reference range of 3.91-5.45 x10E6/uL 2.

Polycythemia Diagnosis

• An increased hematocrit can be caused by primary proliferative polycythemia (PPP), secondary polycythemia, relative polycythemia, or modifications of the red cell mass and plasma volume within their normal ranges 2.
• The patient's hematocrit and hemoglobin levels are elevated, which may indicate polycythemia 3.
• However, the isolated use of proposed Hb/Hct levels as a definer of polycythemia may lead to a substantial increase in unnecessary diagnostic tests 3.

Diagnostic Considerations

• Blood volume studies are not indicated in patients with obvious pulmonary disease or in male patients with an hematocrit over 60% and female patients with an hematocrit over 55% 2.
• The red blood cell count (RBC) may more precisely reflect the total red cell mass and accordingly the hypercoagulable state of the polycythemia vera (PV) patient, which is integrated in the erythrocyte sedimentation rate (ESR) 4.
• A combination of RBC and ESR is proposed as a novel tool to substitute the Hb concentration and the HCT in the diagnosis of PV 4.