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; Shiga-like toxin
CPT4 code
Name of the Procedure:
Infectious Agent Antigen Detection by Immunoassay Technique
Common names: Shiga-like Toxin Immunoassay, EIA, ELISA, IMCA
Summary:
This procedure involves detecting the presence of Shiga-like toxin, a harmful substance produced by certain bacteria, using immunoassay techniques. These methods include enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), and immunochemiluminometric assay (IMCA). The test is qualitative or semiquantitative, determining if the toxin is present and sometimes estimating its amount.
Purpose:
The procedure is designed to identify infections caused by bacteria that produce Shiga-like toxin, such as certain strains of E. coli. The primary goal is to diagnose these infections accurately to guide appropriate treatment.
Indications:
- Severe diarrhea with bloody stools
- Suspected foodborne illnesses
- Symptoms of hemolytic uremic syndrome (HUS), such as kidney failure and low platelet count
- Confirmation of outbreaks caused by toxin-producing bacteria
Preparation:
- No specific patient preparation is usually required.
- Patients might be advised to avoid eating or drinking for a few hours before the test in some cases.
- Any current medications should be discussed with the physician.
Procedure Description:
- Sample Collection: A sample of the patient's stool, blood, or other bodily fluid is collected.
- Antigen Detection: The sample is treated and placed on a special plate or test strip.
- Binding and Reaction: Antibodies specific to the Shiga-like toxin bind to any toxins present. A reaction occurs, often involving an enzyme that produces a color change or light emission.
- Reading Results: The intensity of the color or light indicates the presence and possibly the amount of Shiga-like toxin, read using specialized equipment.
Duration:
The procedure typically takes a few hours to yield results, although the time can vary based on the specific assay method used.
Setting:
The test is usually performed in a hospital laboratory or specialized outpatient clinic.
Personnel:
- Medical Laboratory Technicians
- Clinical Microbiologists
- Pathologists (for result interpretation)
Risks and Complications:
- There are minimal risks associated with the sample collection, such as slight discomfort during stool or blood sampling.
- Rarely, false positives or negatives may occur, necessitating further testing for confirmation.
Benefits:
- Provides a quick and accurate diagnosis of infections caused by Shiga-like toxin-producing bacteria.
- Helps initiate appropriate and timely treatment.
- Assists in preventing the spread of infections during outbreaks.
Recovery:
- Most patients require no specific recovery time.
- Normal activities can be resumed immediately after sample collection.
- Follow-up may involve additional tests or treatments based on the results.
Alternatives:
- Bacterial culture to identify the specific strain of bacteria, which may take longer.
- PCR (Polymerase Chain Reaction) assays for rapid genetic detection of bacterial toxins.
- Pros: Culture and PCR can provide more detailed information; Cons: They may be more time-consuming or costly.
Patient Experience:
- Patients may experience minor discomfort during sample collection.
- There is generally no pain or significant side effects associated with the immunoassay itself.
- Comfortable measures and pain management are usually not required.