Search all medical codes

Immunoassay for infectious agent antibody, quantitative, not otherwise specified

CPT4 code

Name of the Procedure:

Immunoassay for Infectious Agent Antibody, Quantitative, Not Otherwise Specified


An immunoassay for infectious agent antibody is a blood test that measures the quantity of specific antibodies in your blood. These antibodies are produced by your immune system in response to an infection.


The primary purpose of this test is to diagnose or monitor infections by detecting antibodies your immune system has created. It helps doctors understand whether you have been exposed to a particular infection and how your body is responding to it.


  • Unexplained symptoms such as fever, fatigue, or body aches.
  • Follow-up testing for previously diagnosed infections.
  • Monitoring chronic infections or evaluating the effectiveness of a treatment.
  • Immune status check before immunosuppressive treatments.


  • Fasting is generally not required.
  • Inform your doctor of any medications or supplements you are taking, as some can affect antibody levels.
  • No specific diagnostic tests are typically required beforehand.

Procedure Description

  1. A healthcare professional will clean the site of the blood draw, usually the arm.
  2. A needle is inserted into a vein to collect a blood sample.
  3. The blood sample is then sent to a laboratory where the immunoassay is performed.
  4. The test measures the quantity of specific antibodies related to the infectious agent in question.


  • Sterile needle and syringe or a vacuum tube system.
  • Laboratory immunoassay equipment.


  • Not required for this blood test.


The blood draw typically takes a few minutes, while lab analysis may take several hours to a few days.


  • Outpatient clinic
  • Hospital
  • Diagnostic laboratory


  • Phlebotomist or nurse for blood draw
  • Laboratory technician for immunoassay analysis
  • Physician to interpret results

Risks and Complications


  • Mild pain or bruising at the site of the blood draw Rare:
  • Infection at the puncture site
  • Fainting or dizziness


  • Accurate diagnosis of infections
  • Effective monitoring of treatment response
  • Insight into immune response to specific infections
  • Results are typically available within a few days


  • No significant recovery time needed.
  • Apply pressure to the puncture site to minimize bruising.
  • Normal activities can usually be resumed immediately.


  • Qualitative immunoassay, which only detects the presence of antibodies.
  • PCR (Polymerase Chain Reaction) testing to detect the genetic material of the infectious agent.
  • Advantages of quantitative immunoassay: precise measurement of antibody levels.
  • Disadvantages: may be more expensive and require specialized lab services.

Patient Experience

  • During the procedure: mild discomfort when the needle is inserted.
  • After the procedure: slight bruising or tenderness that resolves quickly.
  • Pain management: typically not required, over-the-counter pain relief can be used if needed.

Similar Codes