HESI A2 Study Guide
Your area-by-area roadmap
The HESI A2 covers seven content areas across math, English language, and science. Programs choose which sections they require, so confirm your school's list first, then study one area at a time and reinforce it with flashcards and a full-length timed test.
Mathematics
Math · basic operations applied to healthcare
Arithmetic and measurement in nursing contexts: fractions, decimals, percents, ratios and proportions, unit conversions, and simple algebra word problems.
Numbers, operations & measurement
- Be fluent converting among fractions, decimals, and percents.
- Master ratios and proportions — the basis of dosage and dilution problems.
- Know metric and household measurement conversions (kg↔g, L↔mL, etc.).
- Follow order of operations exactly and check the final step.
Applied problem solving
- Translate word problems into one equation before solving.
- Compute means and read values from simple tables.
- Estimate first so an unreasonable answer stands out.
High-yield takeaways
- Percent-of, ratio, and unit-conversion problems appear the most — drill them to automaticity.
- Watch units throughout; a units mistake is the most common error.
Reading
Reading Comprehension · passage-based
Short passages followed by questions on main idea, supporting detail, inference, author's purpose and tone, and vocabulary in context.
Read for structure
- Identify the main idea and each paragraph's role before answering.
- Separate the main idea from supporting details.
- Note the author's purpose and tone from word choice.
Answer from the passage
- Inference questions ask what must follow from the text, not what is merely plausible.
- Return to the passage to confirm detail answers.
- Use context to define vocabulary-in-context items.
High-yield takeaways
- The best main-idea answer covers the whole passage without overreaching.
- Do not bring in outside knowledge — answer only from the passage.
Vocabulary
Vocabulary & General Knowledge · healthcare-flavored
General and health-related vocabulary: definitions, synonyms and antonyms, correct usage in a sentence, and common medical word parts.
Build word power
- Learn common medical roots and affixes (hypo-, -ectomy, -itis, etio-).
- Distinguish synonyms from antonyms — decide what the question wants first.
- Use sentence context to choose the correct word.
High-yield takeaways
- Prefixes and suffixes unlock many unfamiliar medical terms.
- Watch for near-synonyms among the distractors that are related but not exact.
Grammar
Grammar · standard written English
Parts of speech, subject-verb agreement, pronoun case, verb tense, punctuation, modifiers, and clear sentence construction.
Core grammar
- Match verbs to the true subject, ignoring intervening phrases.
- Use the correct pronoun case (who/whom, between you and me).
- Keep verb tense consistent and use past perfect for the earlier of two past actions.
Punctuation & structure
- Join independent clauses with a semicolon or a comma plus conjunction.
- Set off nonessential clauses with commas; keep essential clauses unpunctuated.
- Avoid fragments, run-ons, and dangling or misplaced modifiers.
High-yield takeaways
- Subject-verb agreement and comma/semicolon rules are the most frequently tested.
- Read the whole sentence — the error is often not where it first seems.
Biology
Biology · cellular and molecular basics
Cell structure and function, cellular respiration and photosynthesis, mitosis and meiosis, DNA and base pairing, transport, and enzymes.
Cells & molecules
- Know organelle functions (mitochondria make ATP; ribosomes build proteins).
- Understand passive vs. active transport and osmosis (hyper-/hypotonic).
- Master DNA base pairing (A–T, C–G) and the role of enzymes.
High-yield takeaways
- Cellular respiration, transport, and DNA pairing recur across exams.
- Enzyme questions hinge on shape and how temperature/pH affect it.
Chemistry
Chemistry · foundations
Atomic structure, the periodic table, chemical bonding and formulas, balancing equations, physical vs. chemical change, and the pH scale.
Atoms, bonds & reactions
- Atomic number equals the number of protons; balance charges to write formulas.
- Balance simple equations and count atoms on each side.
- Distinguish physical changes (melting) from chemical changes.
- Remember each pH unit is a tenfold change in hydrogen-ion concentration.
High-yield takeaways
- Ionic charge balancing and pH-scale reasoning show up repeatedly.
- Know the difference between physical and chemical changes cold.
Anatomy & Physiology
Anatomy & Physiology · body systems
Major body systems and how structure supports function, anatomical terminology, homeostasis, and how systems respond to activity and stress.
Systems & function
- Learn each major system and how its structures connect to function.
- Understand homeostasis and feedback (e.g., heart rate, blood pressure).
- Know anatomical directional terms and body planes.
High-yield takeaways
- Structure-to-function relationships are tested more than isolated facts.
- Cardiovascular, respiratory, and nervous systems are the highest-yield.
Ready to practice?
Reinforce what you reviewed with flashcards or a timed test.