ICD-10 K51.00 is officially defined as "Ulcerative (chronic) pancolitis without complications." code K51.00 is referenced in 21 tracked payer policy changes from Independence Blue Cross and Aetna. For billers and coders, staying current on payer-specific coverage criteria, reimbursement rules, and prior-authorization requirements for code K51.00 is critical to clean claim submission. Each entry below links to the full policy analysis with effective dates and action steps.
Independence Blue Cross updated policy 08.02.19b for mirikizumab-mrkz (Omvoh) IV effective 10/19/2026. Coverage criteria were revised to align with updated ACG guidelines, removing conventional therapy requirements. Billing teams must now append modifier JA to indicate intravenous administration, and must use the reintroduced ICD-10 diagnosis codes for ulcerative colitis and Crohn's disease claims.
Independence Blue Cross Medicare Advantage revised its policy for IV mirikizumab-mrkz (Omvoh, HCPCS J2267) for ulcerative colitis and Crohn disease, effective October 19, 2026. The policy reinstates a list of UC and CD ICD-10 diagnosis codes and requires modifier JA for intravenous administration, and coverage depends on the medical necessity criteria being documented.
Aetna considers measurement of antidrug antibodies and or serum drug levels for adalimumab, certolizumab, golimumab, or infliximab medically necessary for members with Crohn's disease or ulcerative colitis when there is documentation of a loss of response to one of these medications, or for proactive monitoring in members 21 years of age or younger with a confirmed diagnosis of IBD. Aetna considers serum antibody measurements for anti-TNF therapies experimental, investigational, or unproven for all other indications, such as psoriasis, psoriatic arthritis, rheumatoid arthritis, spondyloarthritis, and uveitis. Anti-histone antibody measurement for monitoring infliximab and DNA or mRNA biomarker measurement for predicting therapeutic response in IBD are also considered experimental, investigational, or unproven.
Aetna considers measurement of antidrug antibodies and/or serum drug levels to adalimumab, certolizumab, golimumab or infliximab medically necessary for members with inflammatory bowel disease (Crohn's disease or ulcerative colitis) when there is documentation of a loss of response to one of these medications, or for proactive monitoring in members 21 years of age or younger with a confirmed IBD diagnosis. Measurement of anti-histone antibodies for monitoring infliximab therapy and measurement of DNA or mRNA biomarkers for predicting therapeutic response in IBD are considered experimental, investigational or unproven. Serum level and antibody testing of anti-TNF blocking agents for all other indications, such as psoriasis, psoriatic arthritis, rheumatoid arthritis, spondyloarthritis and uveitis, is also considered experimental, investigational or unproven.
Aetna's Clinical Policy Bulletin 0783 (reviewed 2026-10-27) confirms that in vivo analysis technologies for gastrointestinal and urothelial lesions, including confocal laser endomicroscopy, narrow-band imaging, chromoendoscopy and optical biopsy systems, are considered experimental, investigational or unproven for the listed indications. Claims for these services with the listed CPT codes (such as 43206, 43252 and +0397T) and ICD-10 diagnoses will be denied under this policy, so billing staff should review how these services are coded and documented before submission.
Aetna considers repository corticotropin injection (Acthar Gel only) medically necessary for infantile spasms in members less than 2 years of age, and considers all other indications experimental, investigational, unproven, or not medically necessary. Precertification of Acthar Gel or Purified Cortrophin Gel is required of all Aetna participating providers and members in applicable plan designs. Purified Cortrophin Gel is considered experimental, investigational, or unproven for infantile spasms because it is not FDA-approved, nor has a compendial use, for this indication, and use of Acthar Gel in combination with Purified Cortrophin Gel is considered experimental, investigational, or unproven.
Aetna considers autologous hematopoietic cell transplantation medically necessary for adults 18 to 69 years old with rapidly progressive scleroderma (systemic sclerosis) at risk of organ failure. This applies when active interstitial lung disease is present with a forced vital capacity or diffusing capacity of the lung for carbon monoxide below 70% of predicted, or when previous scleroderma-related renal disease is present, and the member meets the transplanting institution's selection criteria or, if there are none, has none of the listed exclusion criteria. Aetna considers autologous or allogeneic hematopoietic cell transplantation experimental, investigational, or unproven for conditions including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, myasthenia gravis, type I diabetes mellitus, age-related macular degeneration, amyotrophic lateral sclerosis, polycythemia vera, and thrombotic thrombocytopenic purpura.
Aetna considers nutritional support a medical item only when it is given by feeding tube or intravenously to a member with permanent non-function or disease of the structures that normally permit food to reach the small bowel, or with small bowel disease that impairs digestion and absorption of an oral diet, and when adequate nutrition cannot be met by dietary adjustment or oral supplements. Aetna does not cover nutritional support taken orally unless state law mandates it, and it does not cover banked breast milk, food supplements, specialized infant formulas, or vitamins and minerals taken orally. Parenteral nutrition is considered medically necessary when adequate intake is not possible by oral or tube feeding, such as after documented enteral failure, when the gastrointestinal tract must be totally non-functioning for a period of time, or when structural or functional bowel disease makes oral and tube feedings inappropriate.
Aetna Clinical Policy Bulletin 0863 covers nerve blocks and lists which ones it considers medically necessary. Covered uses include adductor canal, femoral, fascia iliaca, erector spinae plane and transversus abdominis plane blocks for post-operative pain after specific surgeries, and celiac plexus block for cancer pain, while peripheral nerve blocks for chronic pain are covered only as an active component of a comprehensive pain management program. Blocks listed as experimental and investigational include genicular nerve blocks and peripheral nerve blocks used as the sole treatment for chronic non-malignant pain, because the effectiveness of these approaches has not been established.
Aetna considers allogeneic hematopoietic cell transplantation medically necessary for a list of primary immunodeficiency disorders, including adenosine deaminase deficiency, chronic granulomatous disease, common variable immune deficiency (CVID), DiGeorge syndrome, hemophagocytic lymphohistiocytosis, severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome, and others listed in the policy. Aetna considers hematopoietic cell transplantation experimental, investigational, or unproven for activated phosphoinositide 3-kinase delta syndrome, complement deficiency, granulomatous-lymphocytic interstitial lung disease, inflammatory bowel disease, juvenile idiopathic arthritis, and pulmonary alveolar proteinosis, and for autologous transplantation for primary immunodeficiency disorders. TREC testing is considered medically necessary following allogeneic hematopoietic stem cell transplant for SCID.
Aetna's Clinical Policy Bulletin 0606 covers hematopoietic cell transplantation for autoimmune diseases and other listed conditions. Aetna considers autologous transplant medically necessary for adults aged 18 to 69 with rapidly progressive scleroderma (systemic sclerosis) at risk of organ failure when either active interstitial lung disease with an FVC or DLCO below 70% of predicted is present, or previous scleroderma-related renal disease is present, and the member meets the transplanting institution's selection criteria or, where none exist, has none of the listed exclusion criteria. Aetna considers autologous or allogeneic transplant experimental, investigational or unproven for many autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, type 1 diabetes and myasthenia gravis, and for miscellaneous conditions such as age-related macular degeneration, amyotrophic lateral sclerosis, polycythemia vera and thrombotic thrombocytopenic purpura.
Aetna considers the ADAMTS13 assay medically necessary for assessing prognosis in persons with thrombotic thrombocytopenic purpura (TTP), and for distinguishing hematopoietic stem cell transplant-associated thrombotic microangiopathy (HSCT-TMA, also called transplant-associated TMA) from TTP in persons with overlapping features when the test will be used to inform treatment. Aetna considers the assay experimental, investigational, or unproven for the uses it lists because of insufficient evidence, including sepsis-associated thrombotic microangiopathy, hemolytic uremic syndrome, acute myelogenous leukemia, colorectal cancer survival, COVID-19, cerebral infarction, and ADAMTS13 mutation testing for non-cirrhotic portal hypertension.
Aetna's clinical policy bulletin 0655 sets the coverage rules for adalimumab (Humira) and its biosimilars under commercial medical plans. Adalimumab is considered medically necessary for rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, Crohn's disease, ulcerative colitis, plaque psoriasis, hidradenitis suppurativa, non-infectious uveitis, Behcet's disease, pyoderma gangrenosum and immune checkpoint inhibitor-related inflammatory arthritis when the listed criteria are met. The policy also states that Hulio has been discontinued as of 1/1/2026, and that adalimumab-fkjp is the unbranded generic of Hulio.
Aetna considers Omvoh (mirikizumab-mrkz) medically necessary for commercial members with moderately to severely active ulcerative colitis or Crohn's disease only when the member has a contraindication, intolerance or ineffective response to the listed lower-cost targeted immune modulators. For both conditions, the listed alternatives are Entyvio, Skyrizi, either Pyzchiva or Stelara, Tremfya, and either Avsola, Inflectra or Renflexis, with a one-month trial of each. Precertification is required, and Aetna considers continuation of therapy medically necessary for members who achieve or maintain remission or a positive clinical response.
Aetna's Clinical Policy Bulletin for risankizumab-rzaa (Skyrizi) covers the drug for commercial medical plans when the member meets the listed criteria for plaque psoriasis, psoriatic arthritis, Crohn's disease, or ulcerative colitis. Precertification is required for intravenous Skyrizi, and the drug must be prescribed by or in consultation with a dermatologist (plaque psoriasis), a rheumatologist or dermatologist (psoriatic arthritis), or a gastroenterologist (Crohn's disease and ulcerative colitis). Aetna considers all other indications experimental, investigational, or unproven, and considers concomitant use with another biologic or targeted synthetic drug for the same indication experimental.
Feraheme, Ferrlecit, Injectafer, Monoferric and Venofer are medically necessary only for commercial members who have a contraindication, intolerance or ineffective response to the lower cost alternatives generic ferumoxytol, generic iron sucrose, generic sodium ferric gluconate and INFeD (iron dextran) for the labeled indication. Precertification is required for Feraheme, Ferrlecit, generic sodium ferric gluconate, Injectafer, Monoferric, Venofer and generic iron sucrose in applicable plan designs. Intravenous iron is considered experimental, investigational or unproven for other indications, including acute mountain sickness and anemia of inflammation, and it is contraindicated for genetic hemochromatosis or hemochromatosis secondary to iron overload.
Golimumab is covered for commercial plans when the criteria for the requested form and indication are met. Intravenous Simponi Aria is covered for moderately to severely active rheumatoid arthritis given with methotrexate, active psoriatic arthritis, active ankylosing spondylitis, articular juvenile idiopathic arthritis in members 2 years of age or older, and moderate or severe immune checkpoint inhibitor-related inflammatory arthritis. Subcutaneous Simponi is covered for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, moderately to severely active ulcerative colitis, and immune checkpoint inhibitor-related inflammatory arthritis. Concomitant use with another biologic or targeted synthetic drug for the same indication is considered experimental, investigational or unproven, as are Behcet's disease, Crohn's disease, non-infectious uveitis, panuveitis, posterior uveitis and scleritis for intravenous golimumab, plus asthma and sarcoidosis for subcutaneous golimumab.
Aetna considers guselkumab (Tremfya) medically necessary for commercial members with moderate to severe plaque psoriasis, active psoriatic arthritis, moderately to severely active ulcerative colitis, and moderately to severely active Crohn's disease when the listed criteria are met, and considers all other indications experimental, investigational, or unproven. Plaque psoriasis approval requires members to be 6 years of age or older and weigh at least 40 kg, along with body surface area or prior-treatment criteria. Precertification is required for intravenous guselkumab (Tremfya IV) for all Aetna participating providers and members in applicable plan designs.
Aetna's commercial clinical policy bulletin 0844 covers fecal bacteriotherapy. It considers fecal microbiota transplant medically necessary for Clostridium difficile infection (CDI) confirmed by a positive C. difficile toxin stool test that has recurred after at least one course of adequate antibiotic therapy. It considers a single rectal dose of Rebyota (fecal microbiota, live-jslm) medically necessary for preventing CDI when the policy's criteria are met, and it considers other listed indications, including alcoholic hepatitis, Crohn's disease, ulcerative colitis and irritable bowel syndrome, experimental, investigational, or unproven.
As last reviewed on May 21, 2026, Aetna considers multidisciplinary intestinal rehabilitation programs medically necessary for persons with parenteral nutrition-dependent intestinal failure. These programs usually include a team of dietitians, nurses, gastroenterologists, neonatologists and pediatric surgeons, and focus on diet and nutrition, medications, surgery and rehabilitation. Aetna considers intestinal rehabilitation programs experimental, investigational or unproven for all other indications.
Aetna considers plasmapheresis, plasma exchange and therapeutic apheresis medically necessary for a list of indications. These include acute humoral rejection of renal transplants, acute severe neurological deficits from multiple sclerosis that respond poorly to high-dose glucocorticoids, severe (grades 3 to 5) Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP) with severe or life-threatening symptoms, thrombotic thrombocytopenic purpura, and sickle cell disease. Plasmapheresis, plasma exchange or therapeutic apheresis for all other indications, including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, sepsis or septic shock, and ulcerative colitis, is considered experimental, investigational, or unproven.
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