Pathologists’ assistant prerequisites. There are only ~16 NAACLS-accredited PathA programs in the United States, and admission is hyper-competitive — programs admit cohorts of 8 to 18 students per year. The prerequisite stack varies enough between programs that a single oversight can disqualify an applicant from their top-choice program. This guide consolidates the prerequisite requirements across the major programs (Drexel, Quinnipiac, Maryland, Duke, Toledo, Wayne State, Touro, Loma Linda, and the rest), maps the common requirements, flags the program-specific differences, and lays out the safest path to a complete application.
Pathologists’ Assistant (PathA) is a master’s-level credential certified by the ASCP Board of Certification. To sit for the certification exam, applicants must graduate from a NAACLS-accredited PathA master’s program. There are only about 16 such programs in the United States (plus a small number in Canada), and the supply of seats is dramatically smaller than the demand — competitive programs receive 200 to 400 applications per cycle for cohorts of 8 to 18.
That competitive pressure means the prerequisite stack is non-negotiable. Programs use prereq compliance as the first cut in their admissions filter, and a missing or weak prerequisite is sufficient grounds for an automatic rejection. Worse, the prerequisite list varies between programs — Loma Linda wants Organic Chemistry I and II plus Biochemistry as a strong preference; Touro accepts seven semester hours of organic chemistry with biochemistry counting toward three of those hours; Drexel accepts organic and/or biochemistry; the University of Jamestown requires both. Applying to multiple programs without consolidating these differences is how strong applicants end up with surprise rejections.
This guide is the consolidation. It lays out the common prerequisite stack required by virtually every NAACLS PathA program, the program-specific variations that matter most, and a strategy for building a transcript that satisfies the most demanding program in your target list — so a single completed prerequisite stack covers every application you submit.
The complete list of NAACLS-accredited PathA programs is maintained on the AAPA program directory and the NAACLS searchable directory. As of 2026, the US-based programs include:
New programs continue to apply for accreditation — Carroll University in Wisconsin is in the NAACLS pipeline, and additional programs occasionally come online. Always verify current accreditation status on the AAPA or NAACLS directory before relying on any specific program’s status.
Despite the variations between programs, virtually every NAACLS PathA program requires the same core stack. If you build your transcript around this list — and clear the higher bar set by the most demanding programs in your target list — you’ll satisfy the majority of US programs simultaneously.
Every program publishes a minimum GPA — typically 3.00 — but the average GPA of admitted students at the more competitive programs is 3.5 to 3.7. PathA admissions committees use the prerequisite GPA (the science portion specifically) as a heavy weight in their ranking. A B in Organic Chemistry can sink an otherwise strong application; a B+ across the prerequisite stack puts you in competitive territory.
The largest source of program-by-program variation is the chemistry specialization. Some programs require Organic Chemistry only. Some require Organic AND Biochemistry. Some accept Either Organic OR Biochemistry. A small number accept just one semester of either. The decision of which courses to take is driven by your target program list.
| Program | Chemistry specialization requirement | Strategy |
| Loma Linda | Organic Chemistry I AND II required; Biochemistry preferred | Take all three |
| Duke | Organic Chemistry (≥1 semester) AND Biochemistry both listed | Take both |
| Univ. of Jamestown | Organic Chemistry I/II (8 SH) AND Biochemistry (3–4 SH) both required | Take all three |
| Touro | 7 semester hours of organic chemistry; biochemistry can count for 3 of those hours | Take Organic I + Biochem |
| University of Washington | Organic OR Biochemistry — one term | Either works |
| Drexel | Organic and/or Biochemistry | Either works |
| Quinnipiac | Organic Chemistry (one semester min); Biochemistry recommended | Take Organic; add Biochem if applying broadly |
| Maryland | Organic Chemistry (one semester); Biochemistry recommended | Take Organic; add Biochem if applying broadly |
| Wayne State | Organic Chemistry (one semester min); Biochemistry recommended | Take Organic; add Biochem if applying broadly |
| Toledo | Organic Chemistry (one semester); Biochemistry recommended | Take Organic; add Biochem if applying broadly |
If you’re applying to 4 or more PathA programs, the safe path is: General Chemistry I + II + Organic Chemistry I + Biochemistry I. This combination satisfies every program’s chemistry specialization requirement, exceeds the minimum at every program, and gives you the strongest signal to admissions committees that you’ve taken the chemistry side seriously. The total chemistry course count is four (16+ credits), which fits comfortably within a 9–12 month prerequisite-completion timeline.
If you’re applying narrowly — say, only to programs that accept either organic OR biochemistry — you can skip one of them. But the marginal cost of adding a single course to broaden your application options is typically far less than the cost of an unwelcome rejection from a top-choice program.
Every PathA program requires A&P I and II — this is non-negotiable across the board. The variation is in lab format and in whether the course must be taken at a specific level. Some programs (Duke, Maryland) prefer that A&P be taken at upper-division level (300+ course numbers); others (Toledo, Wayne State) accept 200-level A&P from regionally accredited institutions. All accept majors-level online A&P with a substantive lab component when issued from a regionally accredited four-year university.
Genetics is required or strongly preferred by virtually every PathA program. A few programs (Drexel, Quinnipiac) list it as required; most others list it as strongly recommended. Treat it as required regardless of how it’s listed — it’s a small course relative to the chemistry stack and adds significant signaling weight in admissions.
Physics is the most-variable prerequisite. Drexel and University of Washington require one semester. Most other programs treat it as recommended but not required. If you’re applying to programs that require it, take Physics I (algebra-based is fine for PathA — calculus-based is not necessary). If your target list excludes Drexel and UW, you can usually skip it.
GRE requirements have become inconsistent across PathA programs since 2020. A growing number of programs (Touro, Wayne State, several others) now waive the GRE entirely. Others (Maryland, Loma Linda) still require or strongly recommend it. Check each program’s current policy on its official website — the post-pandemic shifts are not always reflected on third-party listings.
All PathA programs strongly recommend or require shadowing a practicing pathologist or pathologists’ assistant. Specific hour requirements vary (Quinnipiac and Drexel: 40+ shadowing hours suggested; Maryland: 80 hours preferred; Loma Linda: documented exposure required). Shadowing is not technically a prerequisite course, but it’s the single most-cited application strengthener in the personal-statement section and admission interviews. Plan to complete this in parallel with your prerequisite coursework.
The strategic insight that saves PathA applicants the most time is this: build your prerequisite stack to satisfy the most demanding program in your target list, and you simultaneously satisfy every less-demanding program. You don’t need a separate transcript for each program — you need one that clears the highest bar.
Use the AAPA program directory to identify programs by region, degree type, and admission deadline. Most successful PathA applicants apply to 4 to 8 programs simultaneously to maximize their odds.
“Most demanding” doesn’t mean the most prestigious — it means the program with the longest prerequisite list, the highest minimum GPA, and the most restrictive recency rules. Loma Linda (Organic I + II + Biochem) is often the program that sets the chemistry bar; University of Jamestown (8 SH organic + 3-4 SH biochem) is similar. If either is on your list, your stack needs to clear their bar.
With Loma Linda or Jamestown in your list, the chemistry side requires General Chemistry I + II + Organic Chemistry I + Organic Chemistry II + Biochemistry I — five courses, ~20 credits. The biology side requires General Biology I + II + Microbiology + A&P I + II + Genetics — six courses, ~24 credits. Plus Statistics or College Algebra, plus English Composition I + II. The full stack is 12–14 courses (40–50 credits), achievable in 12–18 months of self-paced parallel scheduling.
Build a matrix: rows are courses, columns are target programs, cells contain whether each program requires that course. Any course required by at least one program goes in your stack. The matrix becomes your enrollment roadmap and your gap-analysis tool — and it’s the same logic the MLS Prerequisite Checklist uses for clinical lab applicants.
For a non-science bachelor’s degree holder building the full PathA prerequisite stack from scratch, the project is typically 12–18 months and 12–14 courses. For a science-degree holder with most of the biology and general chemistry already complete, the gap is usually 4–6 courses and 6–9 months.
Every PathA program requires prerequisite coursework from a regionally accredited institution — recognized by CHEA and the US Department of Education through one of the seven regional accreditors (HLC, MSCHE, NECHE, NWCCU, SACSCOC, WSCUC). Online and self-paced delivery is widely accepted. Several PathA programs (Touro is the most explicit) state in writing that online prerequisite courses from regionally accredited institutions are accepted on equal footing with in-person coursework.
PrereqCourses.com offers the full PathA prerequisite stack — BIO 135, BIO 140, BIO 210 Microbiology, BIO 270/275 A&P I/II, BIO 282 Genetics, CHEM 151/152 General Chemistry I/II, CHEM 251/252 Organic Chemistry I/II, CHEM 330 Biochemistry I — through Upper Iowa University (HLC accredited). Courses are self-paced, fully online, with monthly start dates and a typical 6–10 week completion window per course. The full PathA stack from a non-science bachelor’s runs roughly $8,000–$10,000 across 12–14 courses — significantly less than a post-baccalaureate program at a four-year university and finishable on a substantially faster timeline.
Yes — provided the issuing institution is regionally accredited. The post-2020 consensus across NAACLS-accredited PathA programs is that online and self-paced delivery is acceptable for prerequisite coursework as long as the institution holds regional accreditation and the course includes a substantive lab component (where applicable). Touro, Drexel, and several others have explicit policies stating this. Older programs that have not formally updated their policies generally apply the same de facto standard.
Both credentials use the NAACLS framework and ASCP certification, but PathA is master’s-level while MLS is bachelor’s-level. PathA programs typically require all the MLS prerequisites (16+16 in biology and chemistry) plus more — a stricter chemistry specialization, A&P at the I and II level, Genetics, sometimes Physics, and a bachelor’s degree in any field. Applicants with a complete MLS prerequisite transcript are usually 60–80% of the way to a PathA prerequisite transcript.
Most PathA programs accept applications with up to 1–2 prerequisites in progress at the time of submission, on the condition that they’re completed before matriculation. Maryland, Drexel, and Wayne State explicitly accept this; Loma Linda and Duke prefer all prerequisites complete at submission. Each program lists its policy on its website. If you have a gap that won’t close before your application deadline, identify a program that accepts in-progress coursework as your fallback target.
The published minimum is typically 3.00. The average GPA of admitted students at the more competitive programs (Duke, Maryland, Drexel, Quinnipiac) is 3.5 to 3.7, with the science prerequisite GPA often weighted more heavily than overall GPA. A 3.5+ science prerequisite GPA puts you in the competitive band; a 3.7+ puts you near the top of the applicant pool.
No. Every NAACLS-accredited PathA program requires at least one semester of organic chemistry, biochemistry, or both. The variation is in which combination satisfies the requirement (see Section 3). There is no PathA program that accepts only General Chemistry I and II as the chemistry stack — you will need a chemistry specialization course at minimum.
PathA prerequisites overlap significantly with medical school prerequisites — both require General Biology I/II, General Chemistry I/II, Organic Chemistry, Microbiology, and (usually) Biochemistry. PathA additionally requires A&P I/II (medical school does not require this as a prereq, since it’s covered in MS1 anatomy). Medical school requires Physics I/II (most PathA programs do not). Applicants with a medical school prerequisite transcript are essentially complete for PathA, with only A&P to add.
Each program publishes its current prerequisite list on its admissions page. The most reliable starting points are: Duke, Drexel, Quinnipiac, Maryland, Toledo, Wayne State, EVMS, Loma Linda, Touro, UW. The AAPA program directory links to all 16+ accredited programs.
PathA admissions are among the most competitive in allied health — 16 NAACLS-accredited programs admitting 8 to 18 students per cohort each, with applicant pools 10 to 20 times larger than seats available. The prerequisite stack is the first cut programs apply, and the stack varies enough between programs that strong applicants regularly miss admission because of a prereq gap they didn’t catch in time.
The safe path is to consolidate. Build your transcript around the most-demanding program in your target list, take Organic Chemistry I + Biochemistry I as your chemistry specialization (this combination satisfies every program), include A&P I and II, Microbiology, Genetics, and round out with Statistics and English Composition. The full stack is 12 to 14 courses for a non-science bachelor’s, achievable in 12 to 18 months on self-paced regionally accredited online coursework.
With a complete prerequisite stack, your application competes on the dimensions that matter to admissions committees — GPA, shadowing hours, personal statement, recommendation letters — rather than getting filtered out at the prereq-compliance gate. That’s the whole point of the consolidation strategy: clear the floor cleanly so the rest of your application has the chance to be evaluated.
If you’re building the full PathA prerequisite stack, the typical sequence is General Biology I and General Chemistry I in parallel from Month 1, then advance through the biology chain (Biology II, Microbiology, A&P I, A&P II, Genetics) and the chemistry chain (Chemistry II, Organic Chemistry I, Biochemistry I). The free Advisory Service maps your existing transcript against your specific PathA target programs and flags exactly which courses are required. New advisory sessions begin on the 1st of every month.
Browse the full course catalog at PrereqCourses.com/courses.
