TTP - Laboratory Evaluation for Thrombotic Thrombocytopenic Purpura Activity of von Willebrand factor-cleaving protease activity - A low value for this enzyme activity is the diagnostic hallmark for the disease, but the assay may not be available for rapid diagnosis ofTTP. If the value is low, tests to detect an inhibitor to the protease can be performed PT, PTT, and fibrinogen levels - Usually normal Fibrin degradation products or D-dimer - Normal or slightly elevated Hemoglobin/hematocrit - Mild-to-moderate decrease in most cases; hemorrhage and hemolysis can result in severe anemia in some patients Haptoglobin - Low as a reflection of intravascular hemolysis Platelet count - Decreased, often in the range of Peripheral blood smear - Shows schistocytes, nucleated RBCs, and decreased platelet number Direct and indirect antiglobulin tests - Negative, ruling out an immune hemolytic anemia Indirect bilirubin - Mild-to-moderate elevation Serum lactate dehydrogenase (LDH) - Elevated, correlating with the severity of hemolysis and possibly tissue damage from ischemia WBC count and differential - Shows a mild leukocytosis with a left shift Urinalysis - Characterized by mild-to-moderate proteinuria and hematuria (without casts) BUN and creatinine - May or may not be elevated, depending on the presence of renal impairment #TTP #ThromboticThrombocytopenicPurpura #Diagnosis #Workup #Hematology
