Infectious agent antigen detection by immunoassay technique, (eg, enzyme immunoassay [EIA], enzyme-linked immunosorbent assay [ELISA], immunochemiluminometric assay [IMCA]) qualitative or semiquantitative, multiple-step method; Streptococcus, group A
CPT4 code
Name of the Procedure:
Infectious Agent Antigen Detection by Immunoassay Technique
Common Names: Streptococcus Group A Antigen Test, Strep A Test, EIA, ELISA, IMCA
Summary
The Streptococcus Group A antigen test involves using an immunoassay technique to detect the presence of antigens related to Streptococcus bacteria in a patient's sample. It can be carried out using different methods such as enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), or immunochemiluminometric assay (IMCA). The test gives qualitative or semiquantitative results to determine if the patient has a Strep A infection.
Purpose
The test primarily addresses the detection of Streptococcus pyogenes (Group A Streptococcus), which causes throat infections like strep throat. The main goal is to quickly and accurately diagnose a Strep A infection to initiate appropriate antibiotic treatment.
Indications
- Sore throat
- Fever
- Swollen lymph nodes
- Red and swollen tonsils, sometimes with white patches or streaks of pus
- Anyone exhibiting symptoms suggestive of a Streptococcus Group A infection
Preparation
- No specific preparation such as fasting is required.
- Patients might be advised to avoid eating or drinking a short time before the test.
- It's important to inform the healthcare provider of any ongoing medications.
Procedure Description
- Sample Collection: A throat swab is obtained from the patient.
- Antigen Extraction: The swab is mixed with a reagent that extracts Group A Streptococcus antigens.
- Immunoassay Performance: The extracted sample is introduced to the immunoassay device (EIA, ELISA, or IMCA).
- Detection: The immunoassay technique involves multiple steps to bind and detect the Streptococcus antigens. Depending on the assay type, this could involve color changes, chemiluminescent reactions, or enzymatic activity.
- Result Interpretation: The test provides a qualitative result (presence or absence of antigens) or a semiquantitative result (estimating the amount of antigen).
Duration
The procedure, from sample collection to result, typically takes about 15-30 minutes.
Setting
- Outpatient clinic
- Doctor's office
- Hospital laboratory
Personnel
- Registered Nurse (RN) or Medical Assistant to collect the sample.
- Laboratory Technologist or Technician to perform the assay.
Risks and Complications
- Minimal risk involved with throat swab collection, including mild discomfort or gagging.
- Rarely, throat irritation might occur.
Benefits
- Rapid and accurate detection of Strep A infection.
- Allows for timely administration of antibiotics to relieve symptoms and prevent complications.
- Reduces the spread of the infection to others.
Recovery
- No specific recovery needed as it is a non-invasive test.
- Patients can resume normal activities immediately after the sample collection.
Alternatives
- Throat culture: More definitive but takes 24-48 hours for results.
- Rapid antigen detection tests (RADTs): Quicker but may be less sensitive than the immunoassay techniques.
Patient Experience
- Brief discomfort during throat swab collection.
- Rapid results and subsequent relief from knowing the diagnosis.
- Minimal pain involved; typically no need for pain management.