Z21 Insurance Policy Changes

ICD-10 Z21 is officially defined as "Asymptomatic human immunodeficiency virus [HIV] infection status." code Z21 is referenced in 22 tracked payer policy changes from Aetna and Independence Blue Cross. For billers and coders, staying current on payer-specific coverage criteria, reimbursement rules, and prior-authorization requirements for code Z21 is critical to clean claim submission. Each entry below links to the full policy analysis with effective dates and action steps.

Aetna · Identified Oct 10, 2026Medium impact
Immune Globulins for Post-Exposure Prophylaxis (CPB 0544, reviewed 2026-10-07)
Aetna considers immune globulins medically necessary for hepatitis B, cytomegalovirus, Rho-D, rabies, varicella zoster, tetanus, vaccinia, botulism, hepatitis A, measles (rubeola) and rubella exposures or conditions, and considers all other indications experimental, investigational, or unproven. Each product has its own initial criteria, such as hepatitis B immune globulin for members who had contact with an individual diagnosed with hepatitis B virus, Rho-D immune globulin for unsensitized Rh-negative women at 24 to 28 weeks gestation unless the father is known to be Rh-negative, and varicella zoster immune globulin for high-risk individuals with significant exposure to varicella. Continuation of therapy for each product is considered medically necessary for all members, including new members, who meet all initial medical necessity criteria.
Aetna · Identified Oct 6, 2026Medium impact
Pegzilarginase-nbln (Loargys) (CPB 1101)
Aetna's new clinical policy bulletin (CPB 1101, source dated 2026-10-06) sets the criteria for pegzilarginase-nbln (Loargys) on commercial medical plans for arginase 1 deficiency in patients aged 2 to under 32. Precertification is required, the drug must be prescribed by or with a metabolic or enzyme disorder specialist, and Aetna treats all other indications as experimental, investigational or unproven. No effective date is stated in the source, so check current applicability before acting.
Aetna · Identified Oct 5, 2026Medium impact
HIV Testing (CPB 0542, reviewed 2026-08-28)
Aetna considers HIV testing medically necessary for screening persons for HIV infection according to the recommendations of the U.S. Preventive Services Task Force and the CDC, starting with an FDA-approved antigen/antibody combination immunoassay. Reactive specimens go to an FDA-approved HIV-1/HIV-2 antibody differentiation immunoassay and, when indicated, an FDA-approved HIV-1 nucleic acid test. Aetna does not cover home HIV test kits that do not require a physician's prescription under any plans.
Aetna · Identified Oct 1, 2026Medium impact
Diagnosis of Vaginitis (CPB 0643, reviewed 2026-09-25)
Aetna's vaginitis diagnosis policy (CPB 0643), last reviewed 09/25/2026, considers nucleic acid amplification or DNA probe tests for trichomonas, Candida and Gardnerella medically necessary for members with dysuria or symptoms of vaginitis. It also considers BVBlue sialidase testing, PCR tests for bacterial vaginosis and Candida, and pH and amine testing medically necessary for women with symptoms. Trichomonas screening is considered medically necessary for women with listed risk factors, including HIV-positive women, new or multiple partners, history of sexually transmitted diseases, exchange of sex for payment, injection drug use, or high-prevalence settings. Routine screening of asymptomatic women for Candida and Gardnerella, Pap smears for the diagnosis of Candida vulvovaginitis, the uBiome SmartJane screen and the 27-organism vaginal pathogen panel are experimental, investigational or unproven, and screening asymptomatic pregnant women for bacterial vaginosis is experimental and not covered.
Aetna · Identified Aug 19, 2026Medium impact
HIV Drug Susceptibility and Resistance Tests (CPB 0316, reviewed 2026-05-21)
Aetna considers HIV drug susceptibility and resistance tests, phenotypic or genotypic, medically necessary during acute new-onset HIV infection, for suboptimal viral load suppression after antiretroviral therapy starts, and for virologic failure during highly active antiretroviral therapy (HAART). Phenotypic and genotypic tests performed at the same time are not medically necessary because the approach is duplicative. HIV tropism testing with phenotypic recombinant virus assays (Trofile) or genotypic HIV V3-loop assays is medically necessary before a CCR5 antagonist such as maraviroc (Selzentry) is started.
Aetna · Identified Aug 19, 2026Medium impact
Varicella and Herpes Zoster Vaccines (CPB 0115, reviewed 2026-03-19)
Aetna Clinical Policy Bulletin 0115 covers varicella vaccine as a preventive service under the CDC ACIP recommendations, and covers the combined MMRV vaccine (ProQuad) as an alternative to separate MMR and varicella vaccines for children 12 months to 12 years where simultaneous administration of MMR and varicella vaccines is indicated. It covers the two-dose recombinant zoster vaccine Shingrix for prevention of herpes zoster in adults aged 50 years and older, in adults aged 50 years and older who previously received Zostavax, and in adults aged 18 years and older who are or will be at increased risk of herpes zoster due to immunodeficiency or immunosuppression. Shingrix is considered experimental, investigational or unproven for treatment of zoster or postherpetic neuralgia, for prevention of primary varicella infection, for repeat booster doses beyond the two-dose series and for all other indications not listed, and Zostavax is no longer available for use in the United States as of November 18, 2020.
Aetna · Identified Aug 18, 2026Medium impact
HIV Testing (CPB 0542, reviewed 2025-11-26)
Aetna considers HIV testing medically necessary for screening according to the recommendations of the U.S. Preventive Services Task Force and the CDC. Initial testing uses an FDA-approved antigen/antibody combination immunoassay, and further testing follows only for reactive results. Aetna does not cover home HIV test kits that do not require a physician's prescription under any plan, including the Confide Home HIV Test and the Home Access HIV Test System.
Aetna · Identified Aug 17, 2026Medium impact
Hepatitis Screening (CPB 0835, reviewed 2025-12-09)
Aetna considers hepatitis B screening medically necessary for listed groups, including people on hemodialysis, blood or organ donors, pregnant women, people with HIV, injection drug users, men who have sex with men, and people born in regions with a 2% or higher HBV prevalence. Hepatitis C screening is medically necessary for listed groups, and one-time HCV testing without prior risk assessment is medically necessary for adults aged 18 years and older. Hepatitis D screening is medically necessary for people with HBsAg-positive hepatitis B infection and significant risk factors, while hepatitis E screening in the peri-transplant period is experimental, investigational, or unproven.
Aetna · Identified Aug 17, 2026Medium impact
Flow Cytometry, Ektacytometry, DNA Ploidy, and S-phase Fraction (CPB 0351, reviewed 2026-05-21)
Aetna considers flow cytometry for cell surface markers medically necessary for listed conditions, including abnormal tissue, bone marrow or blood histology suspicious for lymphoma, leukemia or myelodysplastic syndrome, multiple myeloma, paroxysmal nocturnal hemoglobinuria, primary immunodeficiencies, Sezary syndrome diagnosis, and T-cell monitoring for HIV infection and AIDS. Flow-cytometry-derived DNA ploidy or S-phase fraction is medically necessary only in localized cancers without metastatic disease, namely endometrial adenocarcinoma, gastric cancer, mediastinal neuroblastoma, medulloblastoma, ovarian carcinoma, partial hydatidiform mole, prostatic adenocarcinoma, renal cell adenocarcinoma and urinary bladder carcinoma, and only when the prognostic information will affect treatment decisions. Ektacytometry is medically necessary for red blood cell cytoskeleton and hydration disorders when red blood cell morphology does not provide a clear diagnosis. The red blood cell adhesion index for all indications, DNA ploidy or S-phase testing in breast, cervical, colorectal, non-small cell lung, small cell lung and pediatric intracranial tumors, and microfluidic flow adhesion assays for sickle cell disease are experimental, investigational or unproven.
Aetna · Identified Aug 16, 2026Medium impact
Meningococcal Vaccines (CPB 0356, reviewed 2026-05-22)
Aetna considers the MenACWY, MenB and MenABCWY meningococcal vaccines medically necessary when they follow ACIP recommendations. Routine MenACWY is covered for adolescents aged 11 through 18, MenB is covered for members 10 years of age or older with listed risk factors and for healthy adolescents and young adults aged 16 through 23 based on shared clinical decision-making, and MenABCWY may be used when both MenACWY and MenB are indicated at the same visit. Meningococcal vaccine for all other indications, and saliva testing of antibody levels, are considered experimental, investigational, or unproven.
Aetna · Identified Aug 15, 2026Medium impact
Ibalizumab-uiyk (Trogarzo) (CPB 0936, reviewed 2025-12-30)
Aetna considers ibalizumab-uiyk (Trogarzo) medically necessary for use in combination with an antiretroviral regimen in heavily treatment-experienced adults with multidrug resistant (MDR) HIV-1 infection who are failing current antiretroviral regimen. The criteria require age 18 or older, a viral load greater than 1,000 copies/mL, documented resistance to at least one antiretroviral medication from each of three classes (NRTI, NNRTI and PI) as measured by resistance testing, and at least 6 months of antiretroviral treatment with failure or recent failure (in the last 8 weeks). Aetna considers ibalizumab-uiyk experimental, investigational, or unproven for all other indications.
Aetna · Identified Aug 15, 2026Medium impact
Immune Globulins for Post-Exposure Prophylaxis (CPB 0544, reviewed 2025-12-23)
Reviewed 2025-12-23, Aetna Clinical Policy Bulletin 0544 covers immune globulin products for post-exposure prophylaxis and treatment, including hepatitis B, cytomegalovirus, Rho(D), rabies, varicella zoster, tetanus, measles, rubella, vaccinia, and botulism immune globulins. For each product the policy lists the indications it considers medically necessary and states that all other indications are experimental, investigational, or unproven. Continuation of therapy is considered medically necessary for all members, including new members, who meet the initial criteria. Immune globulin intramuscular injection (GamaSTAN) requires precertification.
Aetna · Identified Aug 15, 2026Medium impact
Hepatitis B Vaccine (CPB 0410, reviewed 2026-07-06)
Aetna considers hepatitis B vaccine medically necessary when it follows CDC ACIP recommendations for members with listed indications, including all infants, unvaccinated children and adolescents under 19, adults aged 19 to 59 who have not previously completed vaccination, and adults 60 and older with risk factors. Revaccination or booster doses are considered medically necessary in listed circumstances when anti-HBs is less than 10 mIU/mL, including infants born to HBsAg-positive mothers, persons on hemodialysis, and health care professionals with an anti-HBs level below that threshold. For persons with normal immune status who have been vaccinated, booster doses are considered not medically necessary. Aetna generally does not cover immunizations required for travel or because of work-related risk. The policy states that in December 2025 the CDC adopted shared clinical decision-making for hepatitis B vaccination of infants born to mothers who test negative for hepatitis B, and that existing recommendations remain unchanged for infants born to HBsAg-positive mothers or mothers with unknown status.
Aetna · Identified Aug 15, 2026Medium impact
Fecal Bacteriotherapy (CPB 0844, reviewed 2026-03-25)
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.
Aetna · Identified Aug 14, 2026Medium impact
Allogeneic Processed Thymus Tissue–agdc (Rethymic) (CPB 1055, reviewed 2025-12-23)
Aetna considers a single administration of allogeneic processed thymus tissue-agdc (Rethymic) medically necessary for immune reconstitution in members 18 years of age or younger with congenital athymia when all criteria are met. Aetna considers all other indications experimental, investigational, or unproven. Members with severe combined immunodeficiency (SCID), preexisting cytomegalovirus or HIV infection, or any prior thymus tissue transplantation or Rethymic treatment are not eligible.
Aetna · Identified Aug 14, 2026Medium impact
Diagnosis of Vaginitis (CPB 0643, reviewed 2025-12-15)
Aetna considers several vaginitis tests medically necessary for women with symptoms of vaginitis, including nucleic acid amplification or DNA probe assays for trichomonas, Candida and Gardnerella for members with dysuria or symptoms of vaginitis, sialidase activity testing such as the BVBlue test, and pH and amine testing of vaginal fluid. Screening for Trichomonas vaginalis is considered medically necessary for women with risk factors such as HIV-positive status, new or multiple partners, a history of sexually transmitted diseases, exchange of sex for payment, injection drug use, or high-prevalence settings such as STD clinics and correctional facilities. A Pap smear for the diagnosis of Candida vulvo-vaginitis, routine screening for Candida and Gardnerella in asymptomatic women, the uBiome SmartJane screen, and the 27-organism vaginal pathogen panel from Bridge Diagnostics are considered experimental, investigational, or unproven because their effectiveness has not been established.
Aetna · Identified Aug 13, 2026Medium impact
Pharmacogenetic and Pharmacodynamic Testing (CPB 0715, reviewed 2025-12-03)
Aetna Clinical Policy Bulletin 0715 (reviewed 2025-12-03) sets coverage rules for pharmacogenetic and pharmacodynamic testing, listing the tests it considers medically necessary for specific drugs and indications, including EGFR, BRAF, KRAS, BRCA, ALK, DPYD, CYP2C19, CYP2D6, HLA-B*1502 and HLA-B*5701 testing. It considers multi-gene pharmacogenetics panels and many other listed tests experimental, investigational or unproven, and it considers several FoundationOne, Guardant360 CDx and oncoReveal panels not medically necessary for particular indications because there is no proven advantage over targeted testing for those indications. This is so check current applicability with Aetna before relying on it.
Aetna · Identified Aug 12, 2026Medium impact
Cabotegravir and Rilpivirine (Cabenuva) (CPB 0987, reviewed 2026-04-02)
Aetna Clinical Policy Bulletin 0987 covers cabotegravir and rilpivirine (Cabenuva) for commercial medical plans and states that precertification is required for Aetna participating providers and members in applicable plan designs. Aetna considers the injectable medically necessary for HIV-1 infection when the member is virologically suppressed (HIV-1 RNA under 50 copies per mL) on a stable antiretroviral regimen with no history of treatment failure and no known or suspected resistance to either drug, or when the member has viremia, a high risk of disease progression (CD4 count under 200 cells per microliter or AIDS-defining complications), cannot achieve or maintain suppression on oral therapy despite intensive adherence support, and the prescriber attests to discussing the risk of resistance. Continuation is medically necessary unless the member has two consecutive HIV-1 RNA levels of 200 copies per mL or more on the requested drug. All other indications are considered experimental, investigational or unproven.
Aetna · Identified Aug 12, 2026Medium impact
Vitamin D Assay (CPB 0945, reviewed 2025-12-23)
Aetna considers measurements of serum 25-hydroxyvitamin D experimental, investigational, or unproven for routine preventive screening. CPT codes 0038U, 82306 and 82652 are covered if selection criteria are met, and ICD-10 codes covered if selection criteria are met include vitamin D deficiency (E55.0 to E55.9), chronic kidney disease (N18.1 to N18.9) and osteoporosis (M80.00xA to M81.8). ICD-10 codes not covered for the indications listed in the policy include malignant neoplasms of the breast (C50.011 to C50.929) and prostate (C61), diabetes mellitus (E08.00 to E13.9), Alzheimer's disease (G30.0 to G30.9) and screening encounters for malignant neoplasms (Z12.0 to Z12.9).
Independence Blue Cross · Effective Mar 4, 2026Low impact
06.02.09g, Human Immunodeficiency Virus (HIV) Genotyping and Phenotyping (Independence Administrators)
This is a routine annual policy reissue with no substantive changes to HIV genotyping and phenotyping coverage criteria. The only modification is a disclaimer language update effective 03/04/2026 that excludes members whose groups have enrolled in the UM vendor program from this policy's applicability.
Aetna · Identified Sep 29, 2026Low impact
Bio-Surgery: Medicinal Leech Therapy and Medical Maggots (CPB 0556, reviewed 2026-09-01)
Aetna's bio-surgery policy (CPB 0556, reviewed September 1, 2026) sets when medicinal leech therapy and medical maggots (bagged larval therapy) are covered, mainly for specific chronic wounds, flap and replant salvage. It lists many other uses, including knee and thumb osteoarthritis, low back pain and burns, as experimental, and the source gives a review date but no effective date.
Aetna · Identified Aug 12, 2026Low impact
Bio-Surgery: Medicinal Leech Therapy and Medical Maggots (CPB 0556, reviewed 2025-12-02)
This is historical material: an older Aetna policy (source dated 2025-12-02) for medicinal leech therapy and medical maggots (CPB 0556) that PolicyChanges found recently, and it states no effective date. It lists leech therapy for venous congestion and flap or replant salvage, and maggot debridement for certain non-healing wounds, as medically necessary, and it names many other uses, including knee osteoarthritis, low back pain and hemorrhoids, as experimental.

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FREQUENTLY ASKED QUESTIONS

What insurance policy changes affect code Z21?

There are 22 tracked policy changes affecting code Z21, including updates from Aetna, Independence Blue Cross. Each change may modify coverage criteria, reimbursement rates, or prior-authorization requirements.

Which payers have updated policy for code Z21?

Payers that have issued tracked updates for code Z21 include: Aetna, Independence Blue Cross.

How do I get notified when code Z21 policy changes?

Create a free account at PolicyChanges.app and save a search filtered to code Z21. You will get an email when new policy changes reference this code: daily or weekly, your choice, on every plan.

Why do payers change policies for code Z21?

Payers revise policies for individual billing codes to align with updated clinical guidelines, CMS rule changes, fraud and abuse prevention measures, or network cost-management goals. Changes can affect medical necessity criteria, place-of-service restrictions, bundling rules, or whether a code requires prior authorization.

All billing codes J3590 C9399 J3490 99215 99213 99202

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Immune Globulins for Post-Exposure Prophylaxis (CPB 0544, reviewed 2026-10-07)

Pegzilarginase-nbln (Loargys) (CPB 1101)

HIV Testing (CPB 0542, reviewed 2026-08-28)

Diagnosis of Vaginitis (CPB 0643, reviewed 2026-09-25)

HIV Drug Susceptibility and Resistance Tests (CPB 0316, reviewed 2026-05-21)

Varicella and Herpes Zoster Vaccines (CPB 0115, reviewed 2026-03-19)

HIV Testing (CPB 0542, reviewed 2025-11-26)

Hepatitis Screening (CPB 0835, reviewed 2025-12-09)

Flow Cytometry, Ektacytometry, DNA Ploidy, and S-phase Fraction (CPB 0351, reviewed 2026-05-21)

Meningococcal Vaccines (CPB 0356, reviewed 2026-05-22)

Ibalizumab-uiyk (Trogarzo) (CPB 0936, reviewed 2025-12-30)

Immune Globulins for Post-Exposure Prophylaxis (CPB 0544, reviewed 2025-12-23)

Hepatitis B Vaccine (CPB 0410, reviewed 2026-07-06)

Fecal Bacteriotherapy (CPB 0844, reviewed 2026-03-25)

Allogeneic Processed Thymus Tissue–agdc (Rethymic) (CPB 1055, reviewed 2025-12-23)

Diagnosis of Vaginitis (CPB 0643, reviewed 2025-12-15)

Pharmacogenetic and Pharmacodynamic Testing (CPB 0715, reviewed 2025-12-03)

Cabotegravir and Rilpivirine (Cabenuva) (CPB 0987, reviewed 2026-04-02)

Vitamin D Assay (CPB 0945, reviewed 2025-12-23)

06.02.09g, Human Immunodeficiency Virus (HIV) Genotyping and Phenotyping (Independence Administrators)

Bio-Surgery: Medicinal Leech Therapy and Medical Maggots (CPB 0556, reviewed 2026-09-01)

Bio-Surgery: Medicinal Leech Therapy and Medical Maggots (CPB 0556, reviewed 2025-12-02)

What insurance policy changes affect code Z21?

Which payers have updated policy for code Z21?

How do I get notified when code Z21 policy changes?

Why do payers change policies for code Z21?