T50.916A: Underdosing of multiple unspecified drugs, medicaments and biological substances, initial encounter

T50.916A, underdosing of multiple unspecified drugs, medicaments and biological substances, initial encounter, is listed as a covered diagnosis in 6 Medicare billing and coding articles that apply to 20 HCPCS Level II codes, including G0480 (Drug test(s), definitive, utilizing (1) drug…), G0483 (Drug test(s), definitive, utilizing (1) drug…), G0482 (Drug test(s), definitive, utilizing (1) drug…). The articles come from 4 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 T50.916A as a covered diagnosis

CodeDescriptionMedicare coverageDMEPOS fee 2026 (state range)Articles listing it
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—4
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—4
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—4
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—4
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—4
J0461Injection, atropine sulfate, 0.01 mgSpecial coverage instructions apply—1
J0153Injection, adenosine, 1 mg (not to be used to report any adenosine phosphate compounds)Special coverage instructions apply—1
J1250Injection, dobutamine hydrochloride, per 250 mgSpecial coverage instructions apply—1
J0280Injection, aminophyllin, up to 250 mgSpecial coverage instructions apply—1
J1245Injection, dipyridamole, per 10 mgSpecial coverage instructions apply—1
A9700Supply of injectable contrast material for use in echocardiography, per studySpecial coverage instructions apply—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

Medicare policy articles listing T50.916A

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 T50 diagnoses (Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances)

Frequently asked questions

Does Medicare cover T50.916A (Underdosing of multiple unspecified drugs, medicaments and…)?

Medicare covers items and services, not diagnoses. 6 Medicare billing and coding articles list T50.916A as a covered diagnosis for 20 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 T50.916A?

The Level II codes from the policies most specific to this diagnosis are G0480 (Drug test(s), definitive, utilizing (1) drug…, 4 articles); G0483 (Drug test(s), definitive, utilizing (1) drug…, 4 articles); G0482 (Drug test(s), definitive, utilizing (1) drug…, 4 articles); G0481 (Drug test(s), definitive, utilizing (1) drug…, 4 articles); G0659 (Drug test(s), definitive, utilizing drug identification…, 4 articles). Code choice depends on the item supplied; check each code's descriptor.

Which Medicare policy articles list T50.916A?

A55001 (Billing and Coding: Urine Drug Testing); A59416 (Billing and Coding: Urine Drug Testing); A54799 (Billing and Coding: Urine Drug Testing), and 3 more articles.

What is ICD-10-CM code T50.916A?

T50.916A is the ICD-10-CM code for underdosing of multiple unspecified drugs, medicaments and biological substances, initial encounter, in category T50 (Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances), chapter 19: Injury, poisoning and other consequences of external causes.

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 19: Injury, poisoning and other consequences of external causes · All diagnoses · HCPCS lookup