RDMS Cheat Sheet 2026: One-Page Review of Must-Know Facts

The Exam at a Glance

This is the one-page version of what you need to know about the Abdomen sonography credential. It is built from the official Abdomen Sonography Examination Content Outline (Version 24.1) and the current Inteleos exam page. If you want the longer treatment of any item, the full RDMS study guide expands on each area, and the complete guide to all four content areas goes domain by domain.

First, the name. In this article, RDMS means Registered Diagnostic Medical Sonographer - Abdomen. The credential is awarded by the American Registry for Diagnostic Medical Sonography (ARDMS), with examinations administered through Inteleos. If you are still orienting yourself, the explainers on what RDMS is and what RDMS stands for cover the basics.

Domain Weights on One Screen

The AB exam is organized into four weighted domains. Your study time should roughly follow these weights, with a small adjustment for your personal weak spots.

Two things jump out. Domain 2 alone is more than two-fifths of the exam, so weakness there is very hard to offset elsewhere. And Domain 3, the physics domain, is the smallest at 8%, which means it deserves focused but proportionate effort rather than the lion's share of your calendar. The reasoning behind that split is unpacked in the article on how hard the RDMS exam really is.

Domain 1 Facts: Anatomy, Perfusion, and Function

Domain 1 is worth 30% of the exam. It rewards candidates who can think about the abdomen as a set of organs with blood supply and physiologic behavior, not just a set of labeled images.

The most useful habit for this domain is to learn normal as a range, not a single picture. Many pathology questions in Domain 2 are really testing whether you can recognize a departure from a normal pattern you already know well.

Domain 2 Facts: Pathology, Vascular Abnormalities, Trauma, and Postoperative Anatomy

This is the heavyweight domain at 42%. It has four distinct strands, and each can generate its own cluster of questions.

Because of its weight, Domain 2 should receive the largest block of your review time and the most image-based practice. A cheat sheet can list the diseases, but only repeated exposure to images teaches you to tell similar-looking findings apart.

Domain 3 Facts: Abdominal Physics

Domain 3 is only 8% of the exam, but it is where many candidates feel least comfortable. Keep the effort proportionate: understand the concepts well enough to apply them to abdominal scanning, and do not let physics crowd out Domain 2.

Note that the general physics foundation is assessed separately through the SPI exam. The abdominal physics domain on the AB exam is about applying those principles in an abdominal context. The next section explains how the two exams fit together.

Domain 4 Facts: Clinical Care, Practice, and Quality Assurance

At 20%, Domain 4 is the second-most-heavily weighted domain after Domain 2 and the third-largest overall. It is easy to treat it as common sense and skip it, which is a mistake, since it has real weight.

These questions often reward careful reading of the scenario. The best answer is usually the one that protects the patient and follows accepted practice, so slow down and read each stem fully.

The SPI + AB Pairing

The single most important structural fact about this credential is that passing both SPI and AB is required for RDMS (AB). SPI is a shared exam that serves as a prerequisite across sonography specialties, and AB is the abdomen specialty exam. They are two separate hurdles that together produce the credential.

That has a practical consequence for your preparation. SPI content and AB content should be studied as two distinct bodies of knowledge. Do not assume that a strong abdominal pathology review will cover SPI, and do not assume that SPI knowledge will carry you through AB. The eligibility and sequencing details live in the article on RDMS requirements, prerequisites, and how to qualify.

Fees, Format, and Scoring Cheat Sheet

These are the logistics worth memorizing before you register. They reflect the current Inteleos exam page for Abdomen.

• Length: approximately 165 questions over 3 hours.
• Format: multiple-choice questions plus image hotspot questions.
• Scoring scale: 300 to 700, with 555 as the passing score.
• Exam fee: $300 USD.

Pacing matters. With roughly 165 questions in 3 hours, you have a little over a minute per item on average, and image-based questions often consume more time than text questions. Practice reading an image quickly and committing to an answer.

For the full financial picture beyond the exam fee, see the RDMS certification cost breakdown. For a deeper explanation of the 555 threshold on the 300-700 scale, read what you need to pass. And when you are ready to plan your testing timeline, the guide to exam dates, windows, and scheduling covers the calendar side.

Pass-Rate Snapshot

Inteleos publishes historical pass rates for the Abdomen exam on its exam page. The figures below are the ones available to us, and they are worth reading in context.

The gap between first-time and overall rates is the headline. Candidates sitting the exam for the first time pass at a noticeably higher rate than the overall pool, which includes repeat testers. The practical lesson is that thorough preparation before the first attempt pays off. A fuller discussion of these numbers is in what the pass-rate data shows.

What a Text Cheat Sheet Cannot Teach

An honest cheat sheet should name its own limits. The AB exam includes image hotspot questions and image-based interpretation, and no text-only resource, including this one, can fully replicate that experience.

Reading that the gallbladder wall may thicken in certain conditions is not the same as recognizing it on a screen, and a list of artifacts is not the same as spotting one in an unfamiliar image. Likewise, a text-only multiple-choice bank cannot reproduce the act of clicking the correct region of an image.

Use this page to organize and retrieve facts, then pair it with image-rich study and practice that includes interpretation. You can run full-length practice under timed conditions on the RDMS practice test site, and keep in mind that practice questions complement, but do not replace, hands-on image exposure from clinical training. If you are earlier in your journey, the overview of RDMS training lays out how that exposure fits into the path.

Mapping Domains to Your Calendar

You only need one structured plan, and it should follow the domain weights. Here is a compact way to sequence your review, tied directly to the AB content outline.

Adjust the length to your own schedule and clinical experience. The point is the order and the proportions: put the heaviest effort where the exam puts the heaviest weight.

Where the Credential Gets You Hired

The RDMS credential is held by sonographers who scan the abdomen, and it is commonly sought by employers that perform abdominal imaging. Hospitals, outpatient imaging centers, and physician practices that include abdominal ultrasound are typical settings. For a look at what these roles involve, see the overview of RDMS jobs.

Questions about earnings and return on investment come up often, and we deliberately avoid quoting unverified figures here. For a careful discussion, read the RDMS salary guide and the analysis of whether the certification is worth it. If you want to understand the credential itself in more depth, the pages on RDMS certification and what RDMS certification is are good starting points.

Frequently Asked Questions