CBDT Passing Score 2026: Exactly What You Need to Pass

How CBDT Scoring Actually Works

If you're searching for "the CBDT passing score," the honest answer is that the International Society for Clinical Densitometry (ISCD) does not publish a fixed raw score, and it doesn't need to. The Certification Council uses a modified Angoff process to set the passing standard, then reports results on a scaled score. That means the difficulty of each form of the exam is factored into where the cutoff lands, rather than every candidate needing to answer a hard-coded number of the 125 scored questions correctly.

In practice, this is good news: it means the passing standard is built around what a minimally competent, entry-level bone densitometry technologist should know across all five domains - not an arbitrary percentage. For a deeper breakdown of how the test is structured question by question, see the CBDT Exam Domains 2026: Complete Guide to All 5 Content Areas.

Why There's No Single "Passing Percentage"

A modified Angoff study works by having subject-matter experts estimate, question by question, how a borderline-competent candidate would perform. Those estimates are aggregated into a cutoff score for that specific exam form, then converted to the scaled score candidates see on their results. Because different forms of the CBDT exam can vary slightly in difficulty, the raw number of correct answers needed to pass can differ from form to form - even though the underlying competency standard stays the same.

This is also why cohort pass rates are not the same thing as a passing-score threshold. ISCD's reported pass rates reflect how a group of candidates performed against the standard in a given year; they don't tell you how many questions you personally need right. For more on how to interpret those year-to-year numbers, read CBDT Pass Rate 2026: What the Data Shows.

Domain Weights and Why They Drive Your Score

Since there's no flat percentage to memorize, the most useful thing you can control is how your preparation time maps to the exam blueprint. The December 2025 candidate handbook allocates the 125 scored questions across five domains as follows:

Notice that Scan Acquisition and Bone Concepts alone account for 56% of the scored exam (39 plus 31 of 125 questions). If your study plan gives these two domains the same attention as Radiation Safety and Science, you are almost certainly under-preparing for more than half the test.

The remaining three domains - Scan Analysis (19%), Technology and Equipment (14%), and Radiation Safety and Science (11%) - still make up 44% of the scored questions combined, so they can't be skipped. For a domain-by-domain study breakdown, see CBDT Study Guide 2026: How to Pass on Your First Attempt.

Exam Format: 150 Questions, 210 Minutes

The CBDT exam is a closed-book, computer-based test delivered at PSI test centers. It contains 150 multiple-choice questions: 125 are scored and 25 are unscored pretest items used to evaluate future exam content. You won't know which 25 are unscored, so every question deserves your full attention. Of the 125 scored questions, 25 are case-based, meaning they present a patient scenario or scan data set you must interpret before answering.

You'll have 210 minutes to complete all 150 questions - that works out to a little over 80 seconds per question on average, though case-based items typically take longer to work through than straightforward recall questions. Pacing yourself so the case-based questions don't eat into time needed for the final domains is a practical skill worth practicing before test day. If you're still weighing how demanding this format is compared to other allied-health credentials, How Hard Is the CBDT Exam? Complete Difficulty Guide 2026 walks through the difficulty factors in more detail.

What Published Pass Rates Do (and Don't) Tell You

ISCD's certification annual reports show pass rates that shift from year to year: 66% of 125 candidates passed in 2025, while a snapshot retrieved in September 2026 showed 73% among 95 candidates for that year. Because the 2026 figure was pulled mid-year, it should be treated as a current-year snapshot rather than a finalized annual result - the number could still shift as more candidates test throughout the year.

Neither figure tells you what score you personally need. They reflect how a cohort of test-takers performed against the Angoff-based standard, influenced by factors like preparation quality and how many first-time versus repeat candidates sat for that cycle. Use these numbers to gauge overall difficulty, not as a target to calculate backward from. The full year-over-year trend is broken down in CBDT Pass Rate 2026: What the Data Shows.

Confirm Eligibility Before You Register

Before you can even sit for the exam, you need to qualify through one of three ISCD-defined routes:

• Holding a current CBDT, CDT, or ARRT(BD) certification in good standing with documented human DXA involvement
• Holding an accredited allied-health qualification
• Earning at least 12 qualifying Category A/CME credits in skeletal health within the preceding 12 months

If you're coming in through the allied-health or continuing-education routes, ISCD also requires at least three months of DXA experience, 100 central patient scans performed at two skeletal sites, and supervisor verification of that hands-on work. These prerequisites exist because the exam assumes real scanning experience - case-based questions in Scan Acquisition and Scan Analysis are written for candidates who have actually positioned patients and reviewed scan output, not just read about it. Full eligibility details are covered in CBDT Requirements 2026: Eligibility, Prerequisites & How to Qualify.

Fees, Retakes, and the 30-Day Rule

Initial exam fees are $375 for ISCD Full/Professional members and $525 for Community members or nonmembers. If you don't pass on your first try, retest fees drop to $200 and $300 respectively - still a meaningful cost, which is one more reason to treat your first attempt seriously rather than as a "test run."

If you do need a retake, you must wait 30 days before submitting a new application. Candidates are allowed up to three attempts within one year of the original failed exam. If you're unsuccessful after three attempts, ISCD requires 12 additional qualifying credits before you can try again. A full cost breakdown, including how membership status affects your total spend, is available in CBDT Certification Cost 2026: Complete Pricing Breakdown. For scheduling specifics around test windows and application deadlines, see CBDT Exam Dates 2026: Testing Windows, Deadlines & Scheduling.

Where to Spend Your Study Hours

Because Scan Acquisition and Bone Concepts carry more than half the scored weight, a simple way to allocate limited study time is to front-load those two domains, then work through the remaining three in proportion to their question counts.

This is a starting framework, not a rigid rule - adjust based on where you feel weakest after an initial practice assessment. For a complete week-by-week study system, see CBDT Study Guide 2026: How to Pass on Your First Attempt, and use our practice test platform to simulate the case-based question format before test day. A condensed reference for last-minute review is also available in the CBDT Cheat Sheet 2026: One-Page Review of Must-Know Facts.

Test Day Rules That Affect Your Score

CBDT is administered as a closed-book exam at PSI test centers. You'll need valid government-issued photo identification that matches your application exactly - mismatches can delay or block your check-in. Personal calculators and outside reference materials are not permitted; if calculations are needed for a question, any tools provided are administered by the test center itself.

ISCD also offers the Quality Bone Densitometry course as optional preparation, though it is not a prerequisite for sitting the exam. Whether or not you take it, running full-length timed practice sessions through a dedicated practice test resource is one of the best ways to get comfortable with the 210-minute pacing before the real thing.

Frequently Asked Questions