- The Short Answer: What an RPhS Actually Is
- Who Issues the Credential and Who Delivers the Exam
- What a Registered Phlebology Sonographer Does
- The Five Exam Domains and Their Weights
- Exam Format: Items, Timing, and Scoring
- Who Can Sit for the Exam
- Fees, Registration, and the 2027 Testing Transition
- Keeping the Credential Active
- Where RPhS Holders Work
- Sequencing Your Preparation Around the Domains
- Frequently Asked Questions
- RPhS stands for Registered Phlebology Sonographer, a venous-focused credential issued by Cardiovascular Credentialing International (CCI).
- The exam has 170 questions (150 scored, 20 unscored) and requires a scaled score of 650 on a 0-900 range.
- Performance of Diagnostic Testing is the heaviest domain at 36%, followed by Patient Diagnosis at 27%.
- The examination fee is USD 365, including a USD 100 non-refundable application-processing component.
The Short Answer: What an RPhS Actually Is
An RPhS is a Registered Phlebology Sonographer: a professional who has passed a certification examination demonstrating competence in venous ultrasound and in the clinical context surrounding vein disease. Phlebology is the medical specialty devoted to veins and their disorders, so the credential reaches beyond scanning technique. It touches patient assessment, diagnostic testing, conservative therapy, and the support of minimally invasive and invasive vein treatment.
If you have seen the acronym elsewhere and wondered whether it is the same thing, this article concerns only the Registered Phlebology Sonographer credential. For related explainers, see our pages on what RPhS stands for and the meaning of RPhS, and for the formal credential overview, visit RPhS certification.
Who Issues the Credential and Who Delivers the Exam
The credential is awarded by Cardiovascular Credentialing International (CCI). Candidates take the examination at a Pearson VUE test center, which means you sit in a proctored, closed-book environment rather than testing from home. Expect to present two acceptable original forms of identification on exam day. You will have access to an on-screen calculator and an erasable board for working through problems.
CCI publishes its eligibility pathways, the examination matrix and task list, and its applicant handbook. The handbook is internally dated January 2024 even though its filename references December 2022, so always confirm details against the current CCI credential page before you apply.
What a Registered Phlebology Sonographer Does
The five exam domains double as a map of the job. A working RPhS typically moves through a cycle that looks like this:
- Preparing the environment and the patient record, with attention to facility safety and information handling.
- Contributing to diagnosis, which means understanding the clinical picture, symptoms, history, and how venous disease presents.
- Performing the ultrasound examination, the technical heart of the role, covering venous insufficiency and obstruction assessment, scanning protocols, and image quality.
- Supporting conservative therapy, such as compression-based management and patient education.
- Supporting minimally invasive and invasive treatment, including ultrasound guidance and procedural roles in vein clinics and vascular practices.
The Five Exam Domains and Their Weights
CCI organizes the exam around five duty/task domains. These are examination objectives, not chapters of a prescribed curriculum, so a good study plan treats them as targets to hit rather than a reading order. The currently published (pre-February 1, 2027) matrix lists these approximate weights:
| Domain | Approximate Weight |
|---|---|
| Domain 1: Maintain Information, Facility, and Safety | 9% |
| Domain 2: Patient Diagnosis | 27% |
| Domain 3: Performance of Diagnostic Testing | 36% |
| Domain 4: Conservative Treatment/Therapy of Patients | 9% |
| Domain 5: Minimally Invasive and Invasive Treatment of Patients | 20% |
A quirk worth noting: these published weights add up to 101%, even though the issuer's total row says 100%. We report the values exactly as printed rather than adjusting them. Treat them as approximate guides to emphasis, not precise item counts.
Domain 3: Performance of Diagnostic Testing (36%)
The largest domain and the one that most rewards hands-on fluency. Expect questions that probe how studies are performed and how findings are recognized.
- Venous duplex technique and protocol selection
- Recognizing normal versus abnormal venous flow and compressibility
- Image optimization and recognizing technical limitations
- Interpreting what an image or waveform is showing, often via image-based items
Domain 2: Patient Diagnosis (27%)
This domain connects symptoms, history, and risk factors to the diagnostic picture, and tests whether you understand why a given study is being ordered.
- Clinical presentation of venous disease
- Relating patient history and findings to diagnostic questions
- Understanding how test results inform the clinical impression
Domain 5: Minimally Invasive and Invasive Treatment of Patients (20%)
The third-largest domain covers the sonographer's role around procedures, an area newer candidates often under-study because it feels remote from daily scanning.
- Procedural support and ultrasound guidance concepts
- Pre- and post-procedure assessment
- Safety considerations during treatment
Domains 1 and 4 (9% each)
Smaller but not trivial. Domain 1 covers information, facility, and safety practices; Domain 4 covers conservative treatment and therapy. Together they account for roughly a fifth of the exam, and they tend to be the most efficient places to pick up points through straightforward recall.
For a deeper walk through each area, see our complete guide to all five RPhS content areas.
Exam Format: Items, Timing, and Scoring
The exam contains 170 questions. Of those, 150 are scored and 20 are unscored items that are not identified, so you must treat every question as if it counts. The appointment runs three hours: two hours and 50 minutes for answering questions, plus ten minutes for the tutorial and post-exam survey.
Question formats
CCI's question-types guidance names four formats that candidates should expect:
- Single-best-answer multiple choice
- Multiple response, where more than one option may be correct
- Image hot spots, where you click a location on an image
- Drag-and-place, where you position items into the correct spots
The image-driven formats matter a great deal for a sonography credential. Practicing only with text-based multiple choice leaves you unprepared for hot spots and drag-and-place items. You may mark items, review them, and revisit them within the time that remains.
How scoring works
The passing score is 650 on a scaled range of 0-900. That is a scaled score, not a raw percentage, so do not translate it into "I need X% correct." We explain this in detail in our guide to the RPhS passing score.
Who Can Sit for the Exam
Every pathway starts with a high-school diploma or GED plus one documented route. The routes differ for sonographers and for physicians and other licensed clinicians.
Sonographer and allied-health routes
- An active RVS or RVT credential plus six months of venous-ultrasound employment.
- A relevant associate degree or 62 semester hours, plus one year of experience.
- A relevant bachelor's degree plus six months of experience.
Each of these three routes also requires 36 relevant CEUs within the preceding four years.
Licensed clinician routes
- A licensed physician associate or nurse practitioner with six months of limited or complete venous-ultrasound experience.
- Physician routes, which require a medical license and combine one of the following: ABVLM certification or an active RVS/RVT/RPVI with 150 studies performed or directly supervised in the preceding two years; 200 such studies in the preceding two years; or a qualifying residency or fellowship with 200 studies during training.
Our RPhS requirements guide walks through qualifying in more detail.
Fees, Registration, and the 2027 Testing Transition
The examination fee is USD 365, which includes a USD 100 non-refundable application-processing component. If you need to retake, you submit a new application and pay a new examination fee. For a full cost picture, see the RPhS certification cost breakdown.
The matrix change you need to know about
This is the most important timing detail for current applicants. CCI publishes two examination matrices with the same five domain headings but different weights:
| Domain | Current Matrix (pre-Feb 1, 2027) | Matrix Effective Feb 1, 2027 |
|---|---|---|
| Maintain Information, Facility, and Safety | 9% | 7% |
| Patient Diagnosis | 27% | 25% |
| Performance of Diagnostic Testing | 36% | 38% |
| Conservative Treatment/Therapy of Patients | 9% | 10% |
| Minimally Invasive and Invasive Treatment of Patients | 20% | 20% |
Beginning February 1, 2027, testing occurs in February and August only. Applications received August 1 through December 31, 2026 are assigned to the February 1-28, 2027 window. Earlier-approved candidates follow their authorization-to-test dates, capped at the end of February 2027.
Key Takeaway
Match your study blueprint to your test date, not to the date you apply. A candidate who applies in October 2026 will be tested in February 2027 and should prepare against the February 2027 matrix. Because both matrices share the same domain names, the difference is in emphasis: the 2027 version shifts a little more weight toward diagnostic testing.
Rescheduling and retakes
The general minimum retake interval is 45 days, but the new February-and-August windows add a further constraint, so a failed attempt may mean a longer wait than 45 days. On rescheduling, CCI's credential page and its FAQ give different notice periods (two full working days versus 24 hours). Follow the instructions in your own appointment confirmation. Our exam dates and scheduling guide tracks the windows and deadlines.
Keeping the Credential Active
Certification does not end at the exam. The renewal structure has two phases:
- Initial certification period: 9 to 12 months. The first renewal costs USD 165, requires Code of Ethics compliance, and carries no CEUs.
- Ongoing three-year renewals: USD 165, ethics compliance, and 36 CEUs, including at least 30 cardiovascular-related credits. Any remaining credits must be medical-related under CCI's dedicated continuing-education policy.
CCI's credential page uses broader any-topic wording, but the more specific medical-related rule is the one to follow. Passing a CCI examination at the full fee can also satisfy triennial CE requirements, but this is an alternative way to meet the CE obligation, not a waiver of other renewal requirements.
Where RPhS Holders Work
Demand for venous-focused sonography comes mainly from settings built around vein care. Typical employers include:
- Dedicated vein clinics and phlebology practices
- Vascular surgery and interventional practices that offer vein treatment
- Hospital and outpatient vascular laboratories
- Physician offices that perform in-house venous duplex studies
The credential is attractive in vein-centered settings because it signals preparation across the whole care pathway, not only imaging. Compensation varies by region, setting, and experience, and we avoid quoting unverified figures here; our RPhS salary guide and analysis of whether the certification is worth it cover the economics, and the RPhS jobs overview looks at the hiring picture.
Sequencing Your Preparation Around the Domains
Because Domains 2 and 3 together carry roughly 63% of the current weighting, they deserve the largest share of your calendar. One practical way to sequence a campaign over several weeks:
Domain 3 foundation
- Work through venous duplex protocols and normal versus abnormal findings
- Practice with image-based items so hot spots feel routine
Domain 2 and clinical correlation
- Link presentation, history, and risk factors to diagnostic reasoning
- Return to Domain 3 weak spots flagged by practice questions
Domains 5, 4, and 1
- Cover procedural support, conservative therapy, and safety/information topics
- Use these smaller domains for quick, high-yield recall
Full-length simulation
- Sit a timed run that mirrors 170 items in under two hours and 50 minutes
- Review every miss against the correct matrix version for your test date
You can build on this with our RPhS study guide and keep key facts handy with the one-page RPhS cheat sheet. To rehearse the actual question formats, try the RPhS practice tests and check your readiness across all five domains on the main practice site.
Frequently Asked Questions
RPhS stands for Registered Phlebology Sonographer. It is a certification from Cardiovascular Credentialing International (CCI) for professionals who perform and support venous ultrasound and vein-disease care.
There are 170 questions in total: 150 scored items and 20 unscored items. The unscored items are not identified, so answer every question carefully. You have two hours and 50 minutes of answering time within a three-hour appointment.
You need a scaled score of 650 on a 0-900 range. This is a scaled score rather than a raw percentage correct, so it cannot be converted into a simple "percent right" target.
Performance of Diagnostic Testing is the largest domain at 36% on the current matrix, followed by Patient Diagnosis at 27%. On the matrix effective February 1, 2027, diagnostic testing rises to 38%.
Applications received August 1-December 31, 2026 are assigned to the February 2027 testing window, so you should prepare against the matrix effective February 1, 2027. Confirm your assigned test date and window with CCI before you finalize your study plan.
Understanding what an RPhS is, and how the credential is built, is the first step toward deciding whether it fits your career. Start with the eligibility route that matches your background, confirm the matrix that applies to your test date, and build your preparation around the domains that carry the most weight.