Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; quantitative, by radioimmunoassay (eg, RIA)
CPT4 code
Name of the Procedure:
Immunoassay for Analyte Other than Infectious Agent Antibody or Infectious Agent Antigen; Quantitative, by Radioimmunoassay (RIA)
Summary
A radioimmunoassay (RIA) is a sensitive laboratory technique used to measure the concentration of a specific substance (analyte) in the blood. This procedure does not target infectious agents but rather focuses on other substances like hormones, drugs, or proteins.
Purpose
This procedure is designed to:
- Quantify the levels of specific substances in the blood
- Help diagnose and monitor various medical conditions, such as hormonal imbalances, drug levels, or protein concentrations
- Enable precise and early detection of abnormalities for timely treatment
Indications
This test may be recommended if you have:
- Symptoms indicating a hormonal disorder (e.g., thyroid dysfunction)
- Need for monitoring specific drug levels in your blood
- Conditions requiring measurement of certain protein levels
- Suspected metabolic or endocrine disorders
Preparation
To prepare for an RIA, you may need to:
- Fast for a specified period if advised
- Inform your healthcare provider about any medications, supplements, or vitamins you are taking
- Complete any preliminary blood tests or assessments as directed
Procedure Description
The RIA procedure involves:
- Drawing a blood sample from a vein in your arm.
- Adding a known quantity of radiolabeled substance to the blood sample.
- Mixing the sample to allow for the binding of the radiolabeled substance with the target analyte.
- Measuring the radioactivity to determine the concentration of the analyte.
Tools and Equipment:
- Needles and syringes for blood collection
- RIA kits with radiolabeled substances
- Gamma counters to measure radioactivity
Anesthesia or Sedation:
- Typically not required
Duration
The blood draw itself takes just a few minutes, while analysis and results can take several hours to days, depending on the laboratory.
Setting
This procedure is usually performed in a:
- Hospital laboratory
- Outpatient clinic
Personnel
Healthcare professionals involved include:
- Laboratory technicians
- Phlebotomists
- Pathologists
Risks and Complications
Common risks include:
- Minor discomfort or bruising at the needle site
Rare risks may include:
- Infection
- Fainting or dizziness during or after the blood draw
Benefits
Expected benefits include:
- Accurate measurement of analyte levels
- Early detection and monitoring of various health conditions allowing for timely intervention
Recovery
Post-procedure care is minimal:
- Keep the puncture site clean and covered
- Monitor for any signs of infection or prolonged bleeding
- You can typically resume normal activities immediately
Alternatives
Other treatment options include:
- Enzyme-linked immunosorbent assay (ELISA)
- Chemiluminescent immunoassay (CLIA)
- High-performance liquid chromatography (HPLC)
Pros and Cons of Alternatives:
- ELISA and CLIA are also highly sensitive but may not be as precise as RIA.
- HPLC is highly accurate but more complex and expensive.
Patient Experience
During the blood draw, you might feel a slight pinch or discomfort. After the procedure, some people might experience minor bruising or discomfort at the site of blood extraction. Pain management or comfort measures typically aren't needed for this type of procedure.