What it covers
Seven domains, and they are far from equal. NHA's test plan gives the number of scored questions in each: Clinical Patient Care 84, Foundational Knowledge and Basic Science 15, Patient Care Coordination and Education 12, Administrative Assisting 12, Communication and Customer Service 12, Anatomy and Physiology 8, and Medical Law and Ethics 7. The percentages in the table further down are those counts out of 150.
Clinical Patient Care is itself divided into six parts, each with its own count: general patient care 28, infection control and safety 15, patient intake and vitals 14, phlebotomy 12, point-of-care testing and laboratory procedures 9, and EKG and cardiovascular testing 6. General patient care alone is larger than any of the six other domains.
How to turn those counts into a study plan is the subject of the separate study guide, linked at the end of this page.