CPT® Code 83518

Official Description

Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, single step method (eg, reagent strip)

Common Language Description

An immunoassay is a laboratory procedure designed to detect the presence of a specific chemical substance, known as an analyte, in a sample. This particular CPT® Code 83518 refers to immunoassays that are utilized for substances other than antibodies or antigens related to infectious agents. The tests can be qualitative, which means they determine whether the analyte is present or absent, or semiquantitative, which provides an approximate measurement of the analyte's concentration. The single-step method, such as a reagent strip, is specifically indicated by this code. This type of testing is commonly employed in the diagnosis and management of various non-infectious diseases and disorders, including but not limited to celiac disease, motor and sensory neuropathy, Crohn's disease, liver disease, and thyroid disease. The immunoassays can target specific immunoglobulin classes or subclasses, such as Asialo IgG, IgM, ganglioside IgG, IgM, and gliadin IgA, IgG. It is important to note that each class or subclass tested using this method is reported separately. For instance, if both gliadin IgA and IgG are tested, the code 83518 would be reported twice. This code is distinct from CPT® Code 83516, which is used for qualitative or semiquantitative immunoassays that employ a multistep method.

1. Indications

The immunoassay described by CPT® Code 83518 is indicated for the detection of various non-infectious analytes. These tests are particularly useful in the evaluation of several medical conditions, including:

Celiac Disease - A chronic autoimmune disorder triggered by the ingestion of gluten, leading to damage in the small intestine.
Motor and Sensory Neuropathy - Conditions affecting the peripheral nerves, which can result in weakness, numbness, and pain.
Crohn's Disease - A type of inflammatory bowel disease that can affect any part of the gastrointestinal tract, causing a range of symptoms.
Liver Disease - A broad category of conditions affecting liver function, which can be assessed through various immunoassays.
Thyroid Disease - Disorders affecting the thyroid gland, which can impact metabolism and overall health.

2. Procedure

The procedure for conducting an immunoassay using CPT® Code 83518 involves several key steps, which are outlined as follows:

Step 1: Sample Collection - A biological sample, typically blood or serum, is collected from the patient. This sample serves as the basis for the immunoassay testing.
Step 2: Preparation of the Reagent Strip - A reagent strip, which contains specific antibodies or reagents that react with the target analyte, is prepared for the test. This strip is designed for a single-step method of analysis.
Step 3: Application of the Sample - The collected sample is applied to the reagent strip. The reagents on the strip will interact with the analyte present in the sample.
Step 4: Interpretation of Results - After a specified incubation period, the results are interpreted. Qualitative results indicate the presence or absence of the analyte, while semiquantitative results provide an estimate of the analyte's concentration based on the intensity of the reaction.
Step 5: Reporting - The results of the immunoassay are documented and reported. If multiple analytes are tested, each will be reported separately, and the appropriate CPT® code will be used for billing.

3. Post-Procedure

Post-procedure care following an immunoassay using CPT® Code 83518 typically involves monitoring the patient for any immediate reactions to the test, although such reactions are rare. The results of the immunoassay will guide further clinical decisions and management of the patient's condition. It is essential for healthcare providers to discuss the results with the patient, including any necessary follow-up tests or treatments based on the findings. Additionally, proper documentation of the test results and any subsequent actions taken is crucial for maintaining accurate medical records and ensuring compliance with billing and coding standards.

Short Descr	IMMUNOASSAY DIPSTICK
Medium Descr	IMMUNOASSAY ANALYTE QUAL/SEMIQUAL SINGLE STEP
Long Descr	Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, single step method (eg, reagent strip)
Status Code	Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	9 - Not Applicable
Multiple Procedures (51)	9 - Concept does not apply.
Bilateral Surgery (50)	9 - Concept does not apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	9 - Concept does not apply.
Co-Surgeons (62)	9 - Concept does not apply.
Team Surgery (66)	9 - Concept does not apply.
Diagnostic Imaging Family	99 - Concept Does Not Apply
CLIA Waived (QW)	Yes
APC Status Indicator	Conditionally packaged laboratory tests
Type of Service (TOS)	5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS)	T1H - Lab tests - other (non-Medicare fee schedule)
MUE	1
CCS Clinical Classification	233 - Laboratory - Chemistry and Hematology

QW	Clia waived test
90	Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
26	Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
GW	Service not related to the hospice patient's terminal condition
SA	Nurse practitioner rendering service in collaboration with a physician