What does a high hemoglobin in a CBC test indicate?

A high hemoglobin level can indicate several conditions, including polycythemia vera, a disorder in which the body produces too many red blood cells. It can also suggest dehydration, as less plasma volume can falsely elevate hemoglobin concentration. Other possible causes include living at high altitudes, where the body compensates for lower oxygen levels by producing more hemoglobin, or lung disease, where oxygenation is impaired. Your doctor will assess these factors along with other test results to determine the exact cause and recommend appropriate treatment or lifestyle changes.