PNH versus HEMPAS
Paroxysmal Nocturnal Hemoglobinuria (PNH):
Patient has hemoglobin in urine on 1st morning voiding but none during day.
Hereditary Erythroblast Multinuclearity with positive acid-serum test (HEMPAS):
This is due to tissues becoming more acidic during the night because of increased CO2 which causes complement to attach to red cells and patient has red cells which are sensitive to complement. The red cell is destroyed as it circulates (intravascular hemolysis) and thus free hemoglobin is excreted by kidneys.
Patient has red cells (type II) that are sensitive to lysis by complement
PNH is positive for sucrose and acid-serum tests while HEMPAS is only positive for acid-serum test.