Medical Laboratory Scientist (MLS) ASCP Exam 2025 – 400 Free Practice Questions to Pass the Exam

Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare hematological condition characterized by the destruction of red blood cells (hemolysis) that occurs at night, leading to the release of hemoglobin into the urine. One of the primary manifestations of this condition is the development of hemolytic anemia, which can result in low hemoglobin levels.

In PNH, the lack of protective proteins on the surface of red blood cells makes them susceptible to complement-mediated lysis, leading to their premature destruction. This destruction of red blood cells is the direct cause of the reduced hemoglobin in the bloodstream, manifesting clinically as symptoms of anemia, such as fatigue and pallor.

Other conditions such as increased eosinophils, high LAP scores, or low platelet counts do not directly relate to the hemolytic processes in PNH. Increased eosinophil levels are often seen in allergic reactions or parasitic infections, while a high leukocyte alkaline phosphatase (LAP) score is often associated with conditions such as chronic myelogenous leukemia. Low platelets may arise in several hematological disorders, but they are not a typical feature of PNH and can vary among individual cases.

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