الوصف
The Cold Agglutinins Test is a blood test used to detect the presence of cold agglutinins, which are autoantibodies (usually IgM) that cause red blood cells (RBCs) to clump together (agglutinate) at low temperatures (typically 0–4°C) leading to the autoimmune hemolytic anemia (AIHA) known as Cold Agglutinin Disease (CAD) which can be primary or secondary to conditions like infections. Nearly all cold agglutinins are positive for the C3d direct antiglobulin test (DAT). A negative C3d DAT should prompt investigation of a possible warm AIHA.
دواعي الإستعمال
Their clinical significance lies in causing hemolysis and symptoms like fatigue, shortness of breath, and circulatory issues like acrocyanosis (bluish extremities) in the cold.
نوع العينة والكمية والشروط
2 ml Serum
إحتياطات خاصة
Collect blood in a Serum Separator Tube (SST) or plain red-top tube. Keep the specimen at 37°C (in warm water) until processing for transport. Do not refrigerate the sample before serum separation, as this may adversely affect test results. After centrifugation, transfer 1 mL of separated serum (minimum 0.25 mL) into a transport tube. Store and transport the separated serum as follows: • Room temperature: Stable for up to 48 hours • Refrigerated: Stable for up to 2 weeks • Frozen: Stable for up to 1 year
المعدل الطبيعي
Normal (Negative) result: <1:40 titre is generally considered negative or clinically insignificant Positive (Abnormal): ≥1:64 may indicate cold agglutinin disease or secondary hemolysis (e.g., due to Mycoplasma pneumoniae, EBV, lymphoma)