Coding Ahead
CasePilot
Medical Coding Assistant
Case2Code
Search and Code Lookup Tool
CareerCenter
Medical Coding Job Board
Log in Register free account

Need help choosing the right code?

Ask CasePilot about procedures, modifiers, bundling, and coding guidance.

Try CasePilot

Official Description

Immunoassay for infectious agent antibody(ies), qualitative or semiquantitative, single-step method (eg, reagent strip);

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

CPT® Code 86318 refers to an immunoassay procedure designed to detect the presence of antibodies against infectious agents. This code specifically applies to qualitative or semiquantitative testing methods that utilize a single-step approach, such as reagent strips or dipsticks. The primary purpose of this immunoassay is to identify whether antibodies are present in a patient's sample, indicating exposure to specific infectious agents. The results from this type of testing are typically available within a short timeframe, usually between 5 to 10 minutes, making it a rapid diagnostic tool. Common infectious agents that may be screened using this method include Helicobacter pylori, influenza viruses (types A and B), infectious mononucleosis, respiratory syncytial virus (RSV), and group A streptococcus. This code is distinct from other related codes, such as CPT® Code 86317, which is used for quantitative measurements of antibody levels rather than qualitative detection.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The immunoassay procedure represented by CPT® Code 86318 is indicated for the detection of antibodies against various infectious agents. This testing is particularly useful in the following scenarios:

  • H. pylori Screening for the presence of antibodies related to Helicobacter pylori, which is associated with gastric infections and ulcers.
  • Influenza Type A and B Testing for antibodies to determine exposure to influenza viruses, aiding in the diagnosis of flu infections.
  • Infectious Mononucleosis Identification of antibodies related to infectious mononucleosis, commonly caused by the Epstein-Barr virus.
  • Respiratory Syncytial Virus (RSV) Detection of antibodies for RSV, which is a significant cause of respiratory infections in infants and young children.
  • Group A Streptococcus Testing for antibodies against group A streptococcus, which can lead to conditions such as strep throat and rheumatic fever.

2. Procedure

The procedure for CPT® Code 86318 involves several key steps to ensure accurate detection of infectious agent antibodies:

  • Sample Collection A sample, typically a small amount of blood, is collected from the patient. This sample serves as the basis for the immunoassay testing.
  • Application of Sample The collected blood sample is applied to the reagent strip or dipstick, which is designed to interact with specific antibodies present in the sample.
  • Reaction Time The sample is allowed to react with the reagents on the strip for a specified period, usually within 5 to 10 minutes. During this time, if antibodies against the targeted infectious agents are present, a visible reaction will occur.
  • Result Interpretation After the reaction time, the results are interpreted based on the presence or absence of a color change or other indicators on the strip, which signifies the presence of antibodies.

3. Post-Procedure

Following the immunoassay procedure coded under CPT® 86318, the results are typically available within minutes, allowing for rapid clinical decision-making. If antibodies are detected, further clinical evaluation may be warranted to confirm the diagnosis and determine appropriate treatment options. In cases where the test result is negative, it may still be necessary to consider additional testing or clinical assessments based on the patient's symptoms and medical history. Proper documentation of the test results and any subsequent actions taken is essential for maintaining accurate medical records and ensuring continuity of care.

Short Descr IA INFECTIOUS AGENT ANTIBODY
Medium Descr IA INFECTIOUS AGT ANTIBODY QUAL/SEMIQ 1STEP METH
Long Descr Immunoassay for infectious agent antibody(ies), 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 2
CCS Clinical Classification 235 - Other Laboratory
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
QW Clia waived test
CR Catastrophe/disaster related
GA Waiver of liability statement issued as required by payer policy, individual case
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
GW Service not related to the hospice patient's terminal condition
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
U6 Medicaid level of care 6, as defined by each state
Date
Action
Notes
2021-01-01 Changed First appearance of change in code book.
2020-04-10 Changed Code description revised.
2020-01-01 Changed Code description changed.
2011-01-01 Changed Short description changed.
Pre-1990 Added Code added.
Code
Description
Code
Description
Code
Description
CasePilot

Get instant expert-level medical coding assistance.

Ask about:
CPT Codes Guidelines Modifiers Crosswalks NCCI Edits Compliance Medicare Coverage
Example: "What is CPT code 99213?" or "Guidelines for E/M services"