G40.813: Lennox-Gastaut syndrome, intractable, with status epilepticus

G40.813, lennox-Gastaut syndrome, intractable, with status epilepticus, is listed as a covered diagnosis in 8 Medicare billing and coding articles that apply to 27 HCPCS Level II codes, including A9552 (Fluorodeoxyglucose f-18 fdg, diagnostic, per study dose…), A9597 (Positron emission tomography radiopharmaceutical…), A9598 (Positron emission tomography radiopharmaceutical…). The articles come from 3 Medicare contractors. A listed diagnosis supports medical necessity only; coverage still depends on the LCD's criteria and on documentation in the medical record.

HCPCS Level II codes with G40.813 as a covered diagnosis

CodeDescriptionMedicare coverageDMEPOS fee 2026 (state range)Articles listing it
A9552Fluorodeoxyglucose f-18 fdg, diagnostic, per study dose, up to 45 millicuriesCarrier judgment—2
A9597Positron emission tomography radiopharmaceutical, diagnostic, for tumor identification, not otherwise classifiedCarrier judgment—2
A9598Positron emission tomography radiopharmaceutical, diagnostic, for non-tumor identification, not otherwise classifiedCarrier judgment—2
A9601Flortaucipir f 18 injection, diagnostic, 1 millicurieCarrier judgment—2
G0451Development testing, with interpretation and report, per standardized instrument formCarrier judgment—2
G0480Drug test(s), definitive, utilizing (1) drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including, but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem and excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase)), (2) stable isotope or other universally recognized internal standards in all samples (e.g., to control for matrix effects, interferences and variations in signal strength), and (3) method or drug-specific calibration and matrix-matched quality control material (e.g., to control for instrument variations and mass spectral drift); qualitative or quantitative, all sources, includes specimen validity testing, per day; 1-7 drug class(es), including metabolite(s) if performedCarrier judgment—1
G0483Drug test(s), definitive, utilizing (1) drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including, but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem and excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase)), (2) stable isotope or other universally recognized internal standards in all samples (e.g., to control for matrix effects, interferences and variations in signal strength), and (3) method or drug-specific calibration and matrix-matched quality control material (e.g., to control for instrument variations and mass spectral drift); qualitative or quantitative, all sources, includes specimen validity testing, per day; 22 or more drug class(es), including metabolite(s) if performedCarrier judgment—1
G0482Drug test(s), definitive, utilizing (1) drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including, but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem and excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase)), (2) stable isotope or other universally recognized internal standards in all samples (e.g., to control for matrix effects, interferences and variations in signal strength), and (3) method or drug-specific calibration and matrix-matched quality control material (e.g., to control for instrument variations and mass spectral drift); qualitative or quantitative, all sources, includes specimen validity testing, per day; 15-21 drug class(es), including metabolite(s) if performedCarrier judgment—1
G0481Drug test(s), definitive, utilizing (1) drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including, but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem and excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase)), (2) stable isotope or other universally recognized internal standards in all samples (e.g., to control for matrix effects, interferences and variations in signal strength), and (3) method or drug-specific calibration and matrix-matched quality control material (e.g., to control for instrument variations and mass spectral drift); qualitative or quantitative, all sources, includes specimen validity testing, per day; 8-14 drug class(es), including metabolite(s) if performedCarrier judgment—1
G0659Drug test(s), definitive, utilizing drug identification methods able to identify individual drugs and distinguish between structural isomers (but not necessarily stereoisomers), including but not limited to gc/ms (any type, single or tandem) and lc/ms (any type, single or tandem), excluding immunoassays (e.g., ia, eia, elisa, emit, fpia) and enzymatic methods (e.g., alcohol dehydrogenase), performed without method or drug-specific calibration, without matrix-matched quality control material, or without use of stable isotope or other universally recognized internal standard(s) for each drug, drug metabolite or drug class per specimen; qualitative or quantitative, all sources, includes specimen validity testing, per day, any number of drug classesCarrier judgment—1
G0278Iliac and/or femoral artery angiography, non-selective, bilateral or ipsilateral to catheter insertion, performed at the same time as cardiac catheterization and/or coronary angiography, includes positioning or placement of the catheter in the distal aorta or ipsilateral femoral or iliac artery, injection of dye, production of permanent images, and radiologic supervision and interpretation (list separately in addition to primary procedure)Carrier judgment—1
G0017Psychotherapy for crisis furnished in an applicable site of service (any place of service at which the non-facility rate for psychotherapy for crisis services applies, other than the office setting); first 60 minutesCarrier judgment—1
G0018Psychotherapy for crisis furnished in an applicable site of service (any place of service at which the non-facility rate for psychotherapy for crisis services applies, other than the office setting); each additional 30 minutes (list separately in addition to code for primary service)Carrier judgment—1
G0560Safety planning interventions, each 20 minutes personally performed by the billing practitioner, including assisting the patient in the identification of the following personalized elements of a safety plan: recognizing warning signs of an impending suicidal or substance use-related crisis; employing internal coping strategies; utilizing social contacts and social settings as a means of distraction from suicidal thoughts or risky substance use; utilizing family members, significant others, caregivers, and/or friends to help resolve the crisis; contacting mental health or substance use disorder professionals or agencies; and making the environment safeCarrier judgment—1
G2187Patients with clinical indications for imaging of the head: head traumaCarrier judgment—1
G2188Patients with clinical indications for imaging of the head: new or change in headache above 50 years of ageCarrier judgment—1
G2189Patients with clinical indications for imaging of the head: abnormal neurologic examCarrier judgment—1
G2190Patients with clinical indications for imaging of the head: headache radiating to the neckCarrier judgment—1
G2191Patients with clinical indications for imaging of the head: positional headachesCarrier judgment—1
G2192Patients with clinical indications for imaging of the head: temporal headaches in patients over 55 years of ageCarrier judgment—1
G2193Patients with clinical indications for imaging of the head: new onset headache in pre-school children or younger (<6 years of age)Carrier judgment—1
G2194Patients with clinical indications for imaging of the head: new onset headache in pediatric patients with disabilities for which headache is a concern as inferred from behaviorCarrier judgment—1
G2195Patients with clinical indications for imaging of the head: occipital headache in childrenCarrier judgment—1
G0219Pet imaging whole body; melanoma for non-covered indicationsNon-covered by MedicareNot covered2
G0235Pet imaging, any site, not otherwise specifiedNon-covered by MedicareNot covered2

2 more codes are listed. See every code with payment by region in Caduvo.

Medicare policy articles listing G40.813

A diagnosis listed as covered in a billing and coding article supports medical necessity for the article's codes; it does not guarantee payment. Coverage depends on the LCD's criteria, the contractor's jurisdiction and documentation in the medical record.

Other G40 diagnoses (Epilepsy and recurrent seizures)

Frequently asked questions

Does Medicare cover G40.813 (Lennox-Gastaut syndrome, intractable, with status…)?

Medicare covers items and services, not diagnoses. 8 Medicare billing and coding articles list G40.813 as a covered diagnosis for 27 HCPCS Level II codes: the diagnosis can support medical necessity for those codes, but payment still depends on the LCD's coverage criteria and the medical record.

Which HCPCS codes can be billed with ICD-10 G40.813?

The Level II codes from the policies most specific to this diagnosis are A9552 (Fluorodeoxyglucose f-18 fdg, diagnostic, per study dose…, 2 articles); A9597 (Positron emission tomography radiopharmaceutical…, 2 articles); A9598 (Positron emission tomography radiopharmaceutical…, 2 articles); A9601 (Flortaucipir f 18 injection, diagnostic, 1 millicurie, 2 articles); G0451 (Development testing, with interpretation and report, per…, 2 articles). Code choice depends on the item supplied; check each code's descriptor.

Which Medicare policy articles list G40.813?

A53134 (Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions); A59049 (Billing and Coding: NCD Coding Article for Positron Emission Tomography (PET) Scans Used for Non-Oncologic Conditions); A56645 (Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing), and 5 more articles.

What is ICD-10-CM code G40.813?

G40.813 is the ICD-10-CM code for lennox-Gastaut syndrome, intractable, with status epilepticus, in category G40 (Epilepsy and recurrent seizures), chapter 6: Diseases of the nervous system.

Next steps

Sources: CMS Medicare Coverage Database billing and coding articles (covered ICD-10 code lists and HCPCS links); ICD-10-CM FY2026; CMS HCPCS Level II release October 2026; CMS DMEPOS fee schedule 2026 (non-rural state fees). Not billing or legal advice.

Chapter 6: Diseases of the nervous system · All diagnoses · HCPCS lookup