Final answer:
The differential for a negative Coombs's test and elevated hematocrit includes non-immune-mediated conditions like G6PD deficiency, polycythemia vera, dehydration, or physiological adaptations to high altitudes. Polycythemia vera requires thorough investigation due to its serious health implications.
Step-by-step explanation:
When evaluating a differential for a patient with a negative Coombs's test and an elevated hematocrit, clinicians must consider a range of possible conditions. The negative Coombs's test suggests that hemolysis, if present, is not immune-mediated, which is typical in cases such as Glucose-6-phosphate dehydrogenase (G6PD) deficiency. When paired with an elevated hematocrit, the differential could include dehydration, polycythemia vera, or physiological adaptations such as those occurring at high altitude.
Polycythemia vera is a serious blood disorder characterized by an overproduction of red blood cells leading to a high hematocrit. It is often diagnosed in older adults and can significantly increase blood viscosity, presenting risks such as high blood pressure and heart strain. Dehydration can cause a relative increase in hematocrit as plasma volume decreases.
Moreover, adaptation to high altitudes causes increased RBC production, a benign form of polycythemia, benefiting athletic performance. Each possible diagnosis must be carefully assessed using a comprehensive clinical evaluation and relevant laboratory tests.