Q21.4: Aortopulmonary septal defect

Q21.4, aortopulmonary septal defect, is listed as a covered diagnosis in 8 Medicare billing and coding articles that apply to 32 HCPCS Level II codes, including J0153 (Injection, adenosine, 1 mg (not to be used to report any…), J1250 (Injection, dobutamine hydrochloride, per 250 mg), J1245 (Injection, dipyridamole, per 10 mg). The articles come from 5 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 Q21.4 as a covered diagnosis

CodeDescriptionMedicare coverageDMEPOS fee 2026 (state range)Articles listing it
J0153Injection, adenosine, 1 mg (not to be used to report any adenosine phosphate compounds)Special coverage instructions apply—5
J1250Injection, dobutamine hydrochloride, per 250 mgSpecial coverage instructions apply—5
J1245Injection, dipyridamole, per 10 mgSpecial coverage instructions apply—5
J0461Injection, atropine sulfate, 0.01 mgSpecial coverage instructions apply—4
J0280Injection, aminophyllin, up to 250 mgSpecial coverage instructions apply—4
A9700Supply of injectable contrast material for use in echocardiography, per studySpecial coverage instructions apply—3
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—2
G0269Placement of occlusive device into either a venous or arterial access site, post surgical or interventional procedure (e.g., angioseal plug, vascular plug)Special coverage instructions apply—2
J3490Unclassified drugsSpecial coverage instructions apply—2
J2785Injection, regadenoson, 0.1 mgCarrier judgment—2
Q9957Injection, perflutren lipid microspheres, per mlCarrier judgment—2
Q9956Injection, octafluoropropane microspheres, per mlCarrier judgment—2
C8921Transthoracic echocardiography with contrast, or without contrast followed by with contrast, for congenital cardiac anomalies; completeSpecial coverage instructions apply—2
C8922Transthoracic echocardiography with contrast, or without contrast followed by with contrast, for congenital cardiac anomalies; follow-up or limited studySpecial coverage instructions apply—2
C8923Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, complete, without spectral or color doppler echocardiographySpecial coverage instructions apply—2
C8924Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, follow-up or limited studySpecial coverage instructions apply—2
C8928Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, during rest and cardiovascular stress test using treadmill, bicycle exercise and/or pharmacologically induced stress, with interpretation and reportSpecial coverage instructions apply—2
C8929Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, complete, with spectral doppler echocardiography, and with color flow doppler echocardiographySpecial coverage instructions apply—2
C8930Transthoracic echocardiography, with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, during rest and cardiovascular stress test using treadmill, bicycle exercise and/or pharmacologically induced stress, with interpretation and report; including performance of continuous electrocardiographic monitoring, with physician supervisionSpecial coverage instructions apply—2
Q9955Injection, perflexane lipid microspheres, per mlCarrier judgment—2
C8925Transesophageal echocardiography (tee) with contrast, or without contrast followed by with contrast, real time with image documentation (2d) (with or without m-mode recording); including probe placement, image acquisition, interpretation and reportSpecial coverage instructions apply—1
C8926Transesophageal echocardiography (tee) with contrast, or without contrast followed by with contrast, for congenital cardiac anomalies; including probe placement, image acquisition, interpretation and reportSpecial coverage instructions apply—1
C8927Transesophageal echocardiography (tee) with contrast, or without contrast followed by with contrast, for monitoring purposes, including probe placement, real time 2-dimensional image acquisition and interpretation leading to ongoing (continuous) assessment of (dynamically changing) cardiac pumping function and to therapeutic measures on an immediate time basisSpecial coverage instructions apply—1
A9500Technetium tc-99m sestamibi, diagnostic, per study doseCarrier judgment—1
A9502Technetium tc-99m tetrofosmin, diagnostic, per study doseCarrier judgment—1

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

Medicare policy articles listing Q21.4

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 Q21 diagnoses (Congenital malformations of cardiac septa)

Frequently asked questions

Does Medicare cover Q21.4 (Aortopulmonary septal defect)?

Medicare covers items and services, not diagnoses. 8 Medicare billing and coding articles list Q21.4 as a covered diagnosis for 32 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 Q21.4?

The Level II codes from the policies most specific to this diagnosis are J0153 (Injection, adenosine, 1 mg (not to be used to report any…, 5 articles); J1250 (Injection, dobutamine hydrochloride, per 250 mg, 5 articles); J1245 (Injection, dipyridamole, per 10 mg, 5 articles); J0461 (Injection, atropine sulfate, 0.01 mg, 4 articles); J0280 (Injection, aminophyllin, up to 250 mg, 4 articles). Code choice depends on the item supplied; check each code's descriptor.

Which Medicare policy articles list Q21.4?

A57179 (Billing and Coding: Transesophageal Echocardiogram); A57183 (Billing and Coding: Cardiovascular Stress Testing, Including Exercise and/or Pharmacological Stress and Stress Echocardiography); A56500 (Billing and Coding: Cardiac Catheterization and Coronary Angiography), and 5 more articles.

What is ICD-10-CM code Q21.4?

Q21.4 is the ICD-10-CM code for aortopulmonary septal defect, in category Q21 (Congenital malformations of cardiac septa), chapter 17: Congenital malformations and chromosomal abnormalities.

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 17: Congenital malformations and chromosomal abnormalities · All diagnoses · HCPCS lookup