From the Research
Laboratory findings in thrombotic thrombocytopenic purpura (TTP) typically include severe thrombocytopenia, microangiopathic hemolytic anemia, elevated lactate dehydrogenase (LDH), and decreased ADAMTS13 activity. The expected laboratory findings in TTP are:
- Severe thrombocytopenia (platelet count usually below 30,000/μL) 1
- Microangiopathic hemolytic anemia with schistocytes (fragmented red blood cells) on peripheral blood smear
- Elevated lactate dehydrogenase (LDH) 2
- Decreased haptoglobin
- Elevated indirect bilirubin
- Negative direct Coombs test
- Elevated reticulocyte count, indicating an attempt by the bone marrow to replace the destroyed red blood cells
- Mild renal dysfunction with elevated creatinine
- Normal coagulation studies (PT, PTT, fibrinogen) The hallmark diagnostic finding is severely reduced ADAMTS13 activity (typically <10%), with most patients having autoantibodies against ADAMTS13 in acquired TTP, as reported in a study published in the Journal of Clinical Medicine 1. Among the provided options, Increased lactate dehydrogenase is a characteristic laboratory finding in TTP, as it indicates hemolysis and tissue damage 2, 3. Additionally, a Platelet count of 50,000–70,000/ mm3 is also consistent with TTP, although platelet counts are usually below 30,000/μL 3. It is essential to note that the diagnosis of TTP should be made promptly, and treatment with plasma exchange and immunosuppression should be initiated immediately if clinical suspicion is high, as untreated TTP has a mortality rate exceeding 90% 1.