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Cold agglutinin; screen

CPT4 code

Name of the Procedure:

Cold Agglutinin Screen (CAS); Cold Agglutinins Test


The Cold Agglutinin Screen is a blood test that checks for the presence of antibodies called cold agglutinins. These antibodies can cause red blood cells to clump together at low temperatures, which may lead to various blood disorders.


This test is used to detect cold agglutinins in the blood, which can help diagnose conditions like cold agglutinin disease (CAD), a type of autoimmune hemolytic anemia. The goal is to identify and manage the underlying cause of symptoms such as anemia, fatigue, and jaundice.


  • Persistent unexplained anemia
  • Symptoms of hemolytic anemia (fatigue, jaundice, dark urine)
  • Chronic cold-induced symptoms (e.g., fingers turning blue in cold weather)
  • Following infectious diseases like Mycoplasma pneumoniae or Epstein-Barr virus


  • Generally, no special preparation is needed.
  • Inform your healthcare provider about any medications you are taking.
  • Fasting is typically not required.

Procedure Description

  1. A healthcare professional will draw a blood sample from a vein in your arm using a sterile needle.
  2. The blood sample is then sent to a laboratory where it is exposed to cold temperatures to observe any agglutination (clumping) of red blood cells.
  3. The lab technician measures the concentration of cold agglutinins and reports the findings to your doctor.

Tools and Equipment:

  • Sterile needle and syringe or blood collection tube
  • Laboratory facilities for blood analysis

Anesthesia or Sedation:

  • None required; only a standard blood draw is performed.


The blood draw takes about 5-10 minutes. Laboratory analysis may take several hours to a few days, depending on the facility.


The blood sample is typically drawn in a clinic, outpatient laboratory, or hospital setting.


  • Phlebotomist or nurse (for blood draw)
  • Laboratory technician or medical technologist (for sample analysis)
  • Physician or hematologist (for result interpretation)

Risks and Complications

Common (Low Risk):

  • Slight pain or bruising at the needle site
  • Dizziness or lightheadedness


  • Infection at the puncture site
  • Excessive bleeding


  • Accurate diagnosis of cold agglutinin-related disorders
  • Informing appropriate treatment plans
  • Early detection of potential complications


  • No specific recovery period required.
  • Patients can resume normal activities immediately after the blood draw.
  • Follow-up appointments may be scheduled to discuss test results and treatment plans.


  • Direct antiglobulin test (DAT or Coombs test)
  • Comprehensive hematological examination


  • Non-invasive
  • Quick and simple procedure


  • May need additional tests to confirm the diagnosis

Patient Experience

During the blood draw, you may feel a brief sting or pinch. Post-procedure, slight bruising or soreness at the needle site is possible but typically resolves quickly. There is no significant pain associated with this procedure, and comfort measures like applying a warm compress to the puncture site can help alleviate any minor discomfort.

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