- RDMS here means Registered Diagnostic Medical Sonographer - Abdomen, awarded by ARDMS through Inteleos.
- You must pass both the SPI exam and the Abdomen (AB) exam to earn this credential.
- The AB exam has about 165 questions over 3 hours, scored 300-700 with 555 required to pass.
- Domain 2 (Pathology, Vascular Abnormalities, Trauma, and Postoperative Anatomy) carries 42% of the exam.
What RDMS Means Here
Several credentials in healthcare share the letters "RDMS," which makes searching for the term confusing. On this site, RDMS refers specifically to the Registered Diagnostic Medical Sonographer - Abdomen credential: a sonography specialty certification focused on ultrasound examination of the abdomen and related structures.
If you have also seen questions like what RDMS stands for or what the RDMS designation means, the short answer is that the title is earned by demonstrating competence in abdominal ultrasound through a standardized, proctored examination. Sonographers who hold it append the letters after their name, much as nurses or radiologic technologists display their own registries.
For a broader overview of how this credential fits into a sonography career, our companion page on RDMS certification covers the credential from the career side, while this article focuses on what the credential is and how its exam is built.
Who Issues the Credential
The credential is governed by the American Registry for Diagnostic Medical Sonography (ARDMS), and the examinations are administered through Inteleos. Inteleos publishes the official exam content outline, the exam logistics page, and the historical pass-rate data referenced later in this article. When you want authoritative answers about scoring, fees, or the topics tested, those issuer documents are the source of truth, not forum posts or third-party summaries.
The Two-Exam Path: SPI Plus Abdomen
Earning the RDMS (Abdomen) credential is not a single-exam event. A candidate must pass both the Sonography Principles and Instrumentation (SPI) exam and the Abdomen (AB) specialty exam. The SPI exam is a shared physics-and-instrumentation exam that serves multiple sonography specialties, while the AB exam tests abdominal-specific knowledge.
| Component | Role in the credential |
|---|---|
| SPI exam | Shared principles and instrumentation exam; required alongside the specialty exam |
| Abdomen (AB) exam | Specialty exam covering abdominal anatomy, pathology, physics as applied to the abdomen, and clinical practice |
| RDMS (Abdomen) | Awarded after passing both |
This structure has a practical consequence for study planning: you should not expect the abdomen exam to re-teach general ultrasound physics from scratch. The SPI exam is where that shared foundation is tested, and the AB exam includes only a smaller abdominal-physics slice. Eligibility and prerequisite pathways are detailed in our guide to RDMS requirements and how to qualify.
What the Abdomen Exam Looks Like
According to the current Inteleos exam page, the Abdomen exam presents approximately 165 questions over 3 hours. Questions are a mix of standard multiple-choice items and image hotspot questions, where you click a location on an ultrasound image or diagram rather than choosing from lettered options. Scores are reported on a 300-700 scale, and a score of 555 is the passing mark. The listed exam fee is $300 USD.
For a closer look at how the 555 threshold works on that 300-700 scale, see our explainer on the RDMS passing score, and for cost planning beyond the exam fee itself, our RDMS certification cost breakdown walks through the full picture. Scheduling logistics are covered in RDMS exam dates and scheduling.
The Four Weighted Domains
The official Abdomen Sonography Examination Content Outline (Version 24.1) divides the exam into four weighted domains. These weights tell you how the exam allocates its questions, and therefore where your study hours should go.
| Domain | Weight |
|---|---|
| Domain 1: Anatomy, Perfusion, and Function | 30% |
| Domain 2: Pathology, Vascular Abnormalities, Trauma, and Postoperative Anatomy | 42% |
| Domain 3: Abdominal Physics | 8% |
| Domain 4: Clinical Care, Practice, and Quality Assurance | 20% |
Domain 1: Anatomy, Perfusion, and Function (30%)
Anatomy, Perfusion, and Function
This domain covers normal structure and normal behavior. You are expected to know what healthy abdominal organs look like on ultrasound and how blood flows to and through them.
- Sonographic appearance and normal variants of the liver, gallbladder and biliary tree, pancreas, spleen, kidneys, and adrenal region
- Abdominal vasculature, including normal flow patterns and perfusion
- Organ function as it relates to what you see and measure
- Surface landmarks and scanning windows used to visualize each structure
Domain 2: Pathology, Vascular Abnormalities, Trauma, and Postoperative Anatomy (42%)
The Largest Domain
At 42%, this is the single biggest block of the exam, larger than any other domain and nearly as large as Domains 1 and 3 combined. A candidate who is strong on normal anatomy but shaky on disease recognition will struggle here.
- Focal and diffuse disease of solid organs, cystic versus solid lesion characterization, and inflammatory and obstructive conditions
- Vascular abnormalities, including abnormal flow findings
- Sonographic findings in abdominal trauma
- Postoperative anatomy: what the abdomen looks like after surgery, and how expected changes differ from complications
Because many of these items rely on image interpretation, this is also the domain where hotspot and image-based questions are most likely to test you. Our deeper walkthrough in the RDMS exam domains guide expands on each content area.
Domain 3: Abdominal Physics (8%)
Abdominal Physics
The smallest domain, but not one to ignore. It applies ultrasound physics to abdominal scanning situations, which is distinct from the broader physics foundation tested on SPI.
- How imaging and Doppler settings affect what you see in abdominal studies
- Recognizing and correcting artifacts that appear in abdominal imaging
- Optimizing image quality for deep or technically difficult patients
Domain 4: Clinical Care, Practice, and Quality Assurance (20%)
Clinical Care, Practice, and Quality Assurance
One in five questions addresses the professional side of sonography: how you care for patients, practice safely, and maintain quality.
- Patient preparation, communication, and safe scanning practice
- Documentation and reporting of findings
- Quality assurance principles in the imaging department
What the Published Pass Rates Show
Inteleos publishes historical pass-rate data for the Abdomen exam. The figures available are:
| Year | First-time test takers | Overall |
|---|---|---|
| 2023 | 72% | 64% |
| 2022 | 69% | 61% |
Two patterns stand out. First, first-time takers pass at a noticeably higher rate than the overall population, which includes repeat attempts. Second, a meaningful share of candidates do not pass on a given attempt, so the exam is genuinely selective rather than a formality. We interpret these numbers in more depth in our RDMS pass rate analysis and in how hard the RDMS exam really is.
Where Abdominal Sonographers Work
Abdominal ultrasound is one of the most widely performed imaging services, so credentialed sonographers are needed across a range of settings. Typical employers include:
- Hospitals, both inpatient and emergency department imaging, where abdominal scans support acute diagnosis and trauma evaluation
- Outpatient imaging centers and radiology practices
- Physician offices and specialty clinics, such as gastroenterology and nephrology practices
- Mobile and regional imaging services that travel to facilities without an on-site sonographer
Employers frequently list ARDMS credentials in job postings, and holding the abdomen credential signals that you have passed the profession's standardized test of abdominal competency. For what the job market looks like, see RDMS jobs; for earnings context, our RDMS salary guide and the RDMS return-on-investment analysis cover those questions without guesswork.
Sequencing Your Prep Around the Weights
The only study-planning idea worth borrowing here is simple: allocate time in proportion to the weights, but sequence it so that visual skills build gradually. One reasonable ordering:
Domain 1 foundations
- Master normal anatomy and normal flow first; you cannot recognize disease without a firm picture of normal
- Review the SPI-related physics you will need if you have not yet passed that exam
Domain 2 immersion
- Spend the largest block of time here, since it is 42% of the exam
- Work organ by organ, pairing each pathology with its sonographic appearance and its vascular and postoperative variations
Domains 3 and 4, then mixed review
- Cover abdominal physics and clinical practice, which are smaller but quicker to consolidate
- Finish with mixed practice, including image-based items, to rehearse switching between domains
A fuller, step-by-step version of this approach appears in our RDMS study guide, and the RDMS cheat sheet offers a compact review sheet for the final stretch. When you are ready to test yourself against realistic questions, the RDMS practice test lets you drill by domain and track which areas need more attention.
Key Takeaway
Treat Domain 2 as your priority and image interpretation as your hardest skill. Strong text recall will not carry you through hotspot questions, so pair every pathology you memorize with real sonographic images.
Where to Go Next
If you are still orienting yourself, there are several quick reads that answer adjacent questions. Our pages on what RDMS certification is and what an RDMS is as a professional cover the credential from different angles. If you are ready to start working toward it, begin with eligibility, then move to the cost and exam-date pages so you can plan a realistic timeline, and use the main practice test platform to check your readiness as you go.
Frequently Asked Questions
It stands for Registered Diagnostic Medical Sonographer - Abdomen. The credential is governed by ARDMS and administered through Inteleos, and it is distinct from other credentials that happen to share the same acronym.
Yes. You must pass both the SPI exam and the Abdomen (AB) specialty exam. SPI is a shared exam, so the abdomen exam does not repeat that material in full.
The current Inteleos exam page lists approximately 165 questions over 3 hours, with a 300-700 score scale and 555 as the passing score. Questions include multiple-choice and image hotspot formats.
Domain 2, Pathology, Vascular Abnormalities, Trauma, and Postoperative Anatomy, is the largest at 42% of the exam. Domain 1 follows at 30%, then Domain 4 at 20% and Domain 3 at 8%.
Not entirely. The exam includes image hotspot and image-based interpretation questions, which a text-only bank cannot fully simulate. Use text practice for knowledge reinforcement and add real ultrasound images for visual skills.