Code Z00.6 and Clinical Trials

Some of our clients have received denials on certain cardiovascular procedure cases (and others) whereby code Z00.6, Encounter for examination for normal comparison and control in clinical research program was not coded, and also WAS NOT in the SECOND code position on the UB-04 claim.  This includes examination of participant or control in clinical research program.

What are Clinical Trials and Studies?

Clinical trials are research studies performed in people that are aimed at evaluating a medical, surgical, or behavioral intervention. They are the primary way that researchers find out if a new treatment, like a new drug or diet or medical device (for example, a pacemaker) is safe and effective in people. Often a clinical trial is used to learn if a new treatment is more effective and/or has less harmful side effects than the standard treatment.

Other clinical trials test ways to find a disease early, sometimes before there are symptoms. Still others test ways to prevent a health problem. A clinical trial may also look at how to make life better for people living with a life-threatening disease or a chronic health problem. Clinical trials sometimes study the role of caregivers or support groups.

Before the U.S. Food and Drug Administration (FDA) approves a clinical trial to begin, scientists perform laboratory tests and studies in animals to test a potential therapy’s safety and efficacy. If these studies show favorable results, the FDA gives approval for the intervention to be tested in humans.

See this site to search for clinical trials.

Why Z00.6, Encounter for examination for normal comparison and control in clinical research program?

Some clients have enrolled in clinical trials for certain procedures and devices or other medical treatments and are a part of the clinical trial registry. It is important for the coder to find out if their facility is participating in clinical trials and which ones they are.  Not all facilities participate.  Usually coders are given this information and specific instructions on the clinical trial and coding of the procedures. Coders should have this information handy when coding as it is easy to overlook the Z00.6 code and place it as the first secondary diagnosis on the claim (such as Palmetto, the Georgia MAC).  Not all payors require it as the first secondary diagnosis, however some do.  It is important to contact your MAC to see their requirements.

Procedures and conditions that may require code Z00.6:  (some can be added down the line)

Please note that there may be other procedures not on this current list that affect your facility. Not all of the possible codes are displayed below.  Coders can contact their facility on which procedures they are participating in clinical trials on.




  • Leadless Pacemakers – for IP & OP procedures – seen with PCS codes 02HK3NZ & 02H63NZ and CPT codes 0387T & 0388T.   Micra™ is the newest and smallest in our line of pacemakers, approved for use in the United States by the FDA in April 2016.


  • IC-HOT clinical trial (Intracoronary Hyperoxemic Oxygen Therapy) in Anterior Acute Myocardial Infarction Patients



  • LAA/LAAC – Percutaneous Left Atrial Appendage Closure – This is the Watchman coded 02L73DK – Occlusion of LAA with Intraluminal Device, percutaneous approach


  • TAVR – Transcatheter Aortic Valve Replacement (Endovascular) & Transapical Aortic Valve Replacement (Thoracotomy Incision) coded: 02RF37Z, 02RF38Z, 02RF3JZ, 02RF3KZ, 02RF37H, 02RF38H, 02RF3JH, 02RF3KH


  • TTVR – Transcatheter edge to edge tricuspid valve repair.  The objective of this early feasibility study is to gain early clinical insight into the performance of the Intrepid transcatheter tricuspid valve replacement (TTVR) system intended for transfemoral access to deliver a self-expanding bioprosthetic valve within the tricuspid valve. Device: Intrepid™ TTVR System.


  • Absorb IV Trial/Absorb BVS device a clinical trial with a new device called the Absorb IV/Absorb BVS Device where a stent is placed in coronary lesions and it absorbs away.  In the news recently, this is a new breakthrough procedure where the newly approved drug-eluting stent is designed to dissolve when it is no longer needed.
    • To make sure we give appropriate advice on how to code these, the 6th character should be “4” for drug eluting intraluminal device.  So, dilation of coronary artery, xx site(s) with drug eluting intraluminal device, percutaneous approach, 027-34-.


  • ARRIVE Study – clinical trial (pregnancy)

    • Purpose:  Among nulliparous women with singleton uncomplicated term pregnancies, elective induction of labor at 39 weeks, compared with expectant management, reduces the risk of severe neonatal morbidity & perinatal mortality.
    • Official Title:  Induction in Nulliparous Women at 39 Weeks to Prevent Adverse Outcomes: A Randomized Controlled Trial


  • CHAP – Chronic Hypertension and Pregnancy (CHAP) Project – The purpose of this study is to evaluate whether a blood pressure treatment strategy during pregnancy to achieve targets that are recommended for non-pregnant reproductive-age adults (<140/90 mmHg) compared ACOG- recommended standard during pregnancy (no treatment unless BP is severe) is effective and safe.  This is seen on pregnancy charts when an antihypertensive therapy is given such as Nifedipine &  Labetalol.


  • TOP – Transfusion of Prematures Trial (TOP) – purpose is to determine whether higher hemoglobin thresholds for transfusing ELBW infants resulting in higher hemoglobin levels lead to improvement in the primary outcome of survival and rates of neurodevelopmental impairment (NDI) at 22-26 months of age, using standardized assessments by Bayley.


  • VEST – VEST Venous Graft External Support Pivotal Study (VEST Pivotal) Brief Summary:  Prospective, multi-center, randomized, within-subject-controlled, trial, enrolling patients with multi vessel atherosclerotic coronary artery disease, scheduled to undergo SVG CABG with arterial grafting of IMA to LAD and two or more saphenous vein grafts. In each patient, one SVG bypass will be randomized to be supported by the VEST, while another will not be supported and serve as control. Thus, the full cohort will provide a basis for comparison between two sets of SVGs: A VEST supported set; and an unsupported set.


Hybrid Coronary Revascularization Trial (added to list 6/1/18)

Study: “Hybrid Coronary Revascularization Trial”, federally-funded by the NHLBI.  This trial is evaluating two treatment strategies: 1) hybrid revascularization (a combination of CABG + PCI) vs. 2) PCI. Trial Info:


Keep in mind there may be more clinical trials going on at your facility. This is not an exhaustive list.

Check with your facility


In need of coding support? We offer both inpatient coding support and outpatient coding support services. Partner with us to replace underperforming coding vendors, get coding backlogs caught up, staff for a FMLA/vacation gap, special projects, to assist in Single Path Coding, or for Total Outsource Coding Support.


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The information contained in this post is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.

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