CPT® Code 0509T

Official Description

Electroretinography (ERG) with interpretation and report, pattern (PERG)

Common Language Description

Electroretinography (ERG) is a diagnostic procedure utilized to assess and evaluate various conditions that impact the retina and optic nerve. This test measures the electrical activity produced by retinal cells in response to light stimuli, providing critical insights into the functionality of the retina. The procedure typically begins with the administration of mydriatic drops to dilate the pupil, which enhances the visibility of the retina during testing. Following this, the patient undergoes a period of dark or light adaptation, lasting several minutes, depending on the specific protocol being followed. This adaptation phase is essential for optimizing the retinal response to the light stimuli that will be presented during the test. During the procedure, electrodes are strategically placed on the surface of the eye, often using dim red illumination to minimize discomfort and interference with the test. Various types of electrodes may be employed, including contact lens electrodes that rest directly on the cornea or gold Mylar tape electrodes positioned between the lower eyelid and the sclera or cornea. These electrodes are connected to a recording device that captures the electrical responses generated by the retina. To ensure accurate readings, the patient's head is stabilized using head and chin supports, preventing any movement that could affect the results. The eye is then subjected to a series of light flashes emitted from a bright light source, which may include LEDs, a strobe lamp, or a full-field dome equipped with its own illumination. The electrical responses elicited by these light flashes are recorded first in a dark environment and subsequently with background lighting. The resulting electrical activity from the retina is captured by the electrodes and digitally represented as a waveform. A specialized form of ERG, known as Pattern ERG (PERG), focuses on eliciting electrical responses from the central retina through alternating checkerboard stimuli. This technique averages the retinal responses to numerous stimuli, yielding a measurable signal that is crucial for evaluating the health of the optic nerve and the functionality of ganglion cells. The findings from this test can be instrumental in the early detection of glaucoma, and a comprehensive written interpretation of the results is provided to the referring physician.

1. Indications

The electroretinography (ERG) procedure is indicated for the diagnosis and evaluation of various conditions affecting the retina and optic nerve. The following are specific indications for performing this test:

Retinal Disorders Assessment of conditions such as retinitis pigmentosa, diabetic retinopathy, and other retinal degenerative diseases.
Optic Nerve Evaluation Evaluation of optic nerve health and function, particularly in cases of suspected optic neuropathy.
Glaucoma Screening Early detection of glaucoma through the assessment of ganglion cell function and optic nerve integrity.
Visual Pathway Assessment Investigation of visual pathway integrity in patients with unexplained vision loss or visual field defects.

2. Procedure

The electroretinography (ERG) procedure involves several critical steps to ensure accurate measurement of the electrical responses from the retina. The following outlines the procedural steps:

Step 1: Pupil Dilation The procedure begins with the instillation of mydriatic drops into the patient's eyes to dilate the pupils. This dilation is essential for allowing maximum light to enter the eye, facilitating a clearer view of the retina during testing.
Step 2: Adaptation Phase After dilation, the patient undergoes a period of dark or light adaptation, lasting several minutes. This phase is crucial as it prepares the retina to respond optimally to the light stimuli that will be presented during the test.
Step 3: Electrode Placement Once adaptation is complete, electrodes are placed on the surface of the eye. This is done using dim red illumination to minimize discomfort. Various electrode types may be used, including contact lens electrodes or gold Mylar tape electrodes, which are positioned appropriately to capture the electrical activity of the retina.
Step 4: Stabilization To ensure that the patient's head remains still throughout the procedure, head and chin supports are utilized. This stabilization is vital for obtaining consistent and reliable readings.
Step 5: Light Stimulation The eye is then stimulated with a series of light flashes from a bright light source, such as LEDs or a strobe lamp. The electrical responses generated by the retina in reaction to these light stimuli are recorded first in a dark environment and then with background lighting.
Step 6: Data Recording The electrical responses captured by the electrodes are recorded and represented digitally as waveforms. This data is essential for analyzing the functionality of the retina and optic nerve.
Step 7: Pattern ERG Testing In the case of Pattern ERG (PERG), alternating checkerboard stimuli are used to elicit electrical responses specifically from the central retina. The responses to numerous stimuli are averaged to produce a measurable signal that provides insights into ganglion cell function.
Step 8: Interpretation Finally, the results of the ERG are evaluated, and a written interpretation of the findings is provided to the referring physician, offering critical information regarding the health of the optic nerve and potential retinal conditions.

3. Post-Procedure

After the electroretinography procedure, patients may experience temporary visual disturbances due to the dilation of their pupils. It is generally recommended that patients avoid driving or engaging in activities that require clear vision until the effects of the mydriatic drops have worn off. The results of the test will be compiled and interpreted, with a written report provided to the referring physician. This report will include detailed findings regarding the electrical responses of the retina, which can assist in diagnosing any underlying conditions affecting the retina or optic nerve. Follow-up appointments may be necessary to discuss the results and any further diagnostic or therapeutic steps that may be indicated based on the findings.

Short Descr	PATTERN ERG W/I&R
Medium Descr	PATTERN ELECTRORETINOGRAPHY W/I&R
Long Descr	Electroretinography (ERG) with interpretation and report, pattern (PERG)
Status Code	Active Code
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	1 - Diagnostic Tests for Radiology Services
Multiple Procedures (51)	7 - Special payment adjustment rules on the technical component (TC) of multiple diagnostic ophthalmology services apply...
Bilateral Surgery (50)	2 - 150% payment adjustment does NOT apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62)	0 - Co-surgeons not permitted for this procedure.
Team Surgery (66)	0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family	99 - Concept Does Not Apply
APC Status Indicator	Procedure or Service, Not Discounted when Multiple
Berenson-Eggers TOS (BETOS)	none
MUE	1

51	Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
GA	Waiver of liability statement issued as required by payer policy, individual case
TC	Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles
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.
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.
79	Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
GW	Service not related to the hospice patient's terminal condition
LT	Left side (used to identify procedures performed on the left side of the body)
RT	Right side (used to identify procedures performed on the right side of the body)