Certified Pediatric Hematology Oncology Nurse (CPHON) Practice Exam 2026 - Free CPHON Practice Questions and Study Guide

In autoimmune hemolytic anemia (AIHA), hemoglobinuria is a common lab finding that results from the destruction of red blood cells and the subsequent release of hemoglobin into the bloodstream. When the hemoglobin concentration exceeds the binding capacity of haptoglobin, free hemoglobin is then excreted through the kidneys, leading to hemoglobinuria. This finding is particularly indicative of intravascular hemolysis, which is a hallmark of AIHA.

In contrast, decreased lactate dehydrogenase (LDH), increased haptoglobin, and decreased reticulocyte count would not typically be associated with AIHA. Elevated LDH is often seen in hemolytic conditions due to increased cell turnover and release of this enzyme from damaged cells. Haptoglobin levels decrease in AIHA due to the binding of free hemoglobin, which is being released as red blood cells are hemolyzed. A decreased reticulocyte count would suggest inadequate bone marrow response to anemia, which is not typically the case in AIHA, where the reticulocyte count is often increased as the bone marrow attempts to compensate for the hemolysis.

Thus, the presence of hemoglobinuria is a significant finding in AIHA, making this the correct answer.