{"id":6195,"date":"2026-03-30T12:42:31","date_gmt":"2026-03-30T12:42:31","guid":{"rendered":"https:\/\/medibillmd.com\/blog\/?p=6195"},"modified":"2026-03-30T12:42:56","modified_gmt":"2026-03-30T12:42:56","slug":"modifier-63","status":"publish","type":"post","link":"https:\/\/medibillmd.com\/blog\/modifier-63\/","title":{"rendered":"Modifier 63: Description, Examples, and Usage Guidelines"},"content":{"rendered":"\n<p>Did you know that, according to UNICEF data, approximately <a href=\"https:\/\/data.unicef.org\/how-many\/how-many-babies-are-born-each-year-in-the-us\/\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">3,657,476<\/a> babies are born in the U.S. each year? These newborns often require immediate or eventual medical attention as they are more prone to diseases, infections, and other health complications.<\/p>\n\n\n\n<p>Infants less than 4 kg require specialized treatment techniques due to anatomical constraints and immature physiology.<\/p>\n\n\n\n<p>Thus, medical practitioners have to pay extra attention to their health recovery. This results in extra equipment and measures taken during medical treatment.&nbsp;<\/p>\n\n\n\n<p>In medical billing, these extra measures are represented by a two-digit modifier: 63. If your medical facility or clinic is treating an infant weighing less than 4 kg, this guide is for you.&nbsp;<\/p>\n\n\n\n<p>Let\u2019s begin with some basics.&nbsp;<\/p>\n\n\n\t\t\t\t<div class=\"wp-block-uagb-table-of-contents uagb-toc__align-left uagb-toc__columns-1 uagb-toc__collapse uagb-block-63c0971f      \"\n\t\t\t\t\tdata-scroll= \"1\"\n\t\t\t\t\tdata-offset= \"30\"\n\t\t\t\t\tstyle=\"\"\n\t\t\t\t>\n\t\t\t\t<div class=\"uagb-toc__wrap\">\n\t\t\t\t\t\t<div class=\"uagb-toc__title\">\n\t\t\t\t\t\t\tTable Of Contents\t\t\t\t\t\t\t\t\t\t\t\t\t<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewBox= \"0 0 384 512\"><path d=\"M192 384c-8.188 0-16.38-3.125-22.62-9.375l-160-160c-12.5-12.5-12.5-32.75 0-45.25s32.75-12.5 45.25 0L192 306.8l137.4-137.4c12.5-12.5 32.75-12.5 45.25 0s12.5 32.75 0 45.25l-160 160C208.4 380.9 200.2 384 192 384z\"><\/path><\/svg>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"uagb-toc__list-wrap \">\n\t\t\t\t\t\t<ol class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#modifier-63-description\" class=\"uagb-toc-link__trigger\">Modifier 63 \u2013 Description<\/a><ul class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#when-do-medical-practitioners-use-this-modifier\" class=\"uagb-toc-link__trigger\">When Do Medical Practitioners Use This Modifier?<\/a><\/li><\/ul><\/li><li class=\"uagb-toc__list\"><a href=\"#scenarios-where-modifier-63-is-applicable\" class=\"uagb-toc-link__trigger\">Scenarios Where Modifier 63 is Applicable<\/a><ul class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#gut-surgery-for-a-sick-preemie\" class=\"uagb-toc-link__trigger\">Gut Surgery for a Sick Preemie<\/a><li class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#heart-switch-for-a-blue-newborn\" class=\"uagb-toc-link__trigger\">Heart Switch for a Blue Newborn<\/a><\/li><\/ul><\/li><\/ul><\/li><li class=\"uagb-toc__list\"><a href=\"#modifier-63-billing-guidelines\" class=\"uagb-toc-link__trigger\">Modifier 63 \u2013 Billing Guidelines<\/a><ul class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#eligibility\" class=\"uagb-toc-link__trigger\">Eligibility\u00a0<\/a><li class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#medical-documentation\" class=\"uagb-toc-link__trigger\">Medical Documentation<\/a><li class=\"uagb-toc__list\"><li class=\"uagb-toc__list\"><a href=\"#payer-specific-requirements\" class=\"uagb-toc-link__trigger\">Payer-Specific Requirements<\/a><\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><li class=\"uagb-toc__list\"><a href=\"#wrapping-it-up\" class=\"uagb-toc-link__trigger\">Wrapping It Up<\/a><\/ul><\/ul><\/ul><\/ol>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Modifier 63 \u2013 Description<\/strong><\/h2>\n\n\n\n<p>The <a href=\"https:\/\/www.aapc.com\/codes\/cpt-modifiers\/63?srsltid=AfmBOoquOwwJT5k6HwtwS6lJmwMCv30Il1ZnwoOgUU8va1o5kfMC9WgB\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">AAPC<\/a> defines modifier 63 as:<\/p>\n\n\n\n<p><strong>&nbsp;A two-digit code <\/strong><strong><em>for a procedure that a provider performs on a neonate or infant weighing up to 4 kg, which is roughly 8.8 pounds.<\/em><\/strong><\/p>\n\n\n\n<p>This modifier is one of the most challenging modifiers to bill, as it involves treating the smallest patients in complex circumstances.&nbsp;<\/p>\n\n\n\n<p>Let\u2019s discuss when medical practitioners need to use this modifier.&nbsp;<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>When Do Medical Practitioners Use This Modifier?<\/strong><\/h3>\n\n\n\n<p>Medical practitioners append the 63 modifier when billing for neonatal care. This care involves specialized equipment or additional measures to care for the patient, particularly in the NICU. Generally speaking, the NICU treats low-birth-weight infants requiring extra attention, skill, and resources.&nbsp;<\/p>\n\n\n\n<p>Modifier 63 was last updated <a href=\"https:\/\/www.aapc.com\/blog\/44314-modifier-63-gets-2019-update\/#:~:text=The%20modifier%20is%20appended%20to%20the%20CPT%C2%AE,The%20modifier%20may%20result%20in%20higher%20reimbursement.\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">in 2019<\/a> and applies to most surgical procedures performed on neonates or infants by medical practitioners. Moreover, this modifier may be used with some cardiovascular procedural codes, but not with modifier 63-exempt codes.\u00a0<\/p>\n\n\n\n<p>Therefore, it\u2019s crucial to learn realistic use cases for the modifier to ensure its correct application in medical billing.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Scenarios Where <\/strong><strong>Modifier 63<\/strong><strong> is Applicable<\/strong><\/h2>\n\n\n\n<p>The 63 modifier can apply to several situations, but the following are some practical scenarios where it may apply:&nbsp;<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Gut Surgery for a Sick Preemie<\/strong><\/h3>\n\n\n\n<p>Imagine a 10-day-old 2.3 kg preemie with a swollen belly, bloody stools, and fever from necrotizing enterocolitis (NEC). The child has been under treatment and observation for days.&nbsp;<\/p>\n\n\n\n<p>The surgeon performs a laparotomy for <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC1295852\/\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">NEC resection<\/a>, documenting specialized pediatric instruments and thermal regulation. It&#8217;s twice as tough: the abdomen is minuscule, so they use micro-tools, warming pads, and gentle moves to avoid shock.\u00a0<\/p>\n\n\n\n<p>The billing team bills it as 44120-63, where 44120 is the procedural code, and 63 represents modifier 63. Note that the claim is submitted with supporting documents to prove medical necessity, because payers reimburse more when the notes prove the additional hurdles and effort.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Heart Switch for a Blue Newborn<\/strong><\/h3>\n\n\n\n<p>Picture a week-old 3.5 kg baby turning blue from transposition of the great arteries (TGA). The medical practitioners intervene. Therefore, the surgeon stops the heart, chills the body, swaps vessels, and repositions the patient\u2019s mini-arteries.&nbsp;<\/p>\n\n\n\n<p>Because the patient\u2019s scale is small, the surgeon has to use pediatric-design tubes for the procedure. The surgeon performs an arterial switch operation (CPT code 33778), using mini cannulae due to the small vessel size.<\/p>\n\n\n\n<p>The medical team bills code 33778 with modifier 63 for reimbursement. They also document struggles, like accessing and repositioning tiny coronary arteries.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Modifier 63<\/strong><strong> \u2013 Billing Guidelines<\/strong><\/h2>\n\n\n\n<p>Understanding the billing guidelines for modifier 63 is imperative for medical billing teams and medical facilities.&nbsp;<\/p>\n\n\n\n<p>Since modifier and CPT code usage guidelines are updated annually, billing teams should remain mindful of these changes to avoid unnecessary billing delays or errors. The following are the factors you must be mindful of when using the 63 modifier to bill the payer:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Eligibility&nbsp;<\/strong><\/h3>\n\n\n\n<p>Understanding the eligibility criteria is the first step to accurate medical billing. According to Moda Health, modifier 63 can only be appended to CPT codes ranging from <a href=\"https:\/\/modahealth.com\/-\/media\/modahealth\/shared\/Provider\/Policies\/RPM062.pdf\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">20005-69990<\/a>, and when procedures are performed on infants weighing less than or equal to 4 kg.\u00a0<\/p>\n\n\n\n<p>In contrast, 63 cannot be used with a few exempt codes (e.g., 33502 and 33503 per <a href=\"https:\/\/www.aapc.com\/codes\/\/download_pdfs\/appendix\/cpt_AppendixF.pdf?srsltid=AfmBOopRLBghRg7kBOPEmgFq0CXZBxots4XudyixHG_qhVsCeNPKj_61\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">CPT Appendix F<\/a>), as the code description specifies that the procedure is for neonates or infants. If the medical billing professional makes this error, it will result in an instant denial.<\/p>\n\n\n\n<p>Some other services that cannot be reported with this modifier include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Anesthesia<\/li>\n\n\n\n<li>Category III code services<\/li>\n\n\n\n<li>Evaluation and management (E\/M) visits<\/li>\n\n\n\n<li>HCPCS codes\u00a0<\/li>\n\n\n\n<li>Integumentary services<\/li>\n\n\n\n<li>Medicine services\u00a0<\/li>\n\n\n\n<li>Pathology\/ lab services<\/li>\n\n\n\n<li>Radiology services<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Medical Documentation<\/strong><\/h3>\n\n\n\n<p>Providing complete medical documentation, patient history, and operative notes is crucial for the successful processing of a claim. For this modifier, the rule remains the same. However, there are a few additional requirements.&nbsp;<\/p>\n\n\n\n<p>For instance, the documentation must confirm the pediatric patient\u2019s weight and justify increased procedural complexity\/ risk. Moreover, it must highlight additional efforts made and equipment used during the invasive surgical procedure.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Payer-Specific Requirements<\/strong><\/h3>\n\n\n\n<p>Modifier 63 is covered by several payers, such as Medicare (Palmetto GBA, Railroad Medicare) and major commercial payers. Each of these payers may have its own prerequisites. Thus, medical practitioners and billing professionals should consider payer-specific requirements while billing.<\/p>\n\n\n\n<p>For instance, Asuris Northwest Health offers <a href=\"https:\/\/www.asuris.com\/web\/asuris_provider\/modifier-63-procedure-performed-on-infants-less-than-4kg?p_p_id=empserviceportlet_WAR_empserviceportlet&amp;p_p_lifecycle=2&amp;p_p_state=normal&amp;p_p_mode=view&amp;p_p_resource_id=getUser&amp;p_p_cacheability=cacheLevelPage\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">120% reimbursement<\/a> for claims with the 63 modifier, but policies for other payers may vary.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Wrapping It Up<\/strong><\/h2>\n\n\n\n<p>Medical practitioners use modifier 63 when an invasive surgical procedure is performed on a neonate or infant weighing up to 4 kg. It requires accurate documentation of the patient\u2019s size and weight, along with medical reports, operative notes, and other supporting documents.&nbsp;<\/p>\n\n\n\n<p>If accurate NICU billing and modifier usage are a challenge for your practice, our <a href=\"https:\/\/medibillmd.com\/services\/medical-billing-services\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>medical billing services<\/strong><\/a> can help you. We employ an expert team of AAPC-certified coders to ensure coding accuracy in every claim.\u00a0\u00a0<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Did you know that, according to UNICEF data, approximately 3,657,476 babies are born in the U.S. each year? These newborns [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":6201,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","content-type":"","_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[16],"tags":[],"class_list":["post-6195","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-modifiers"],"uagb_featured_image_src":{"full":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing.webp",1200,720,false],"thumbnail":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing-150x150.webp",150,150,true],"medium":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing-300x180.webp",300,180,true],"medium_large":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing-768x461.webp",768,461,true],"large":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing-1024x614.webp",1024,614,true],"1536x1536":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing.webp",1200,720,false],"2048x2048":["https:\/\/medibillmd.com\/blog\/wp-content\/uploads\/2026\/03\/What-is-modifier-63-in-medical-Billing.webp",1200,720,false]},"uagb_author_info":{"display_name":"Fred Allen","author_link":"https:\/\/medibillmd.com\/blog\/author\/fred-allen\/"},"uagb_comment_info":0,"uagb_excerpt":"Did you know that, according to UNICEF data, approximately 3,657,476 babies are born in the U.S. each year? These newborns [&hellip;]","_links":{"self":[{"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/posts\/6195","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/comments?post=6195"}],"version-history":[{"count":2,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/posts\/6195\/revisions"}],"predecessor-version":[{"id":6207,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/posts\/6195\/revisions\/6207"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/media\/6201"}],"wp:attachment":[{"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/media?parent=6195"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/categories?post=6195"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medibillmd.com\/blog\/wp-json\/wp\/v2\/tags?post=6195"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}