Lab requisitions under Dr. Latsky
A one-page website that prepares the Ontario Ministry of Health Laboratory
Requisition, form 4422-84 (2026/04), printed under:
Dr. Jason Latsky · 2896 Dundas Street W, Toronto ON M6P 1Y8
Billing 052360 · CPSO 143244
It is for an allied provider to fill in the patient and the tests, print the
form, and have Dr. Latsky sign it. It is not an EMR: nothing is stored, no
patient list, no login. The page sends one order, gets one PDF back, and that
is all.
What it does
- Patient — name as on the health card, date of birth, sex, health number
and version code, address, phone, payer (OHIP / uninsured / WSIB).
- Tests — every tick box on the form, grouped as printed (Biochemistry,
Hematology, Immunology, Microbiology, Viral Hepatitis, PSA), the vitamin D
insured / uninsured choice, and the eleven "Other Tests" free-text lines
with quick-add chips for common tests. A twelfth line prints a second sheet.
- Clinical information, date of service, the date beside the signature,
and an optional "copy of results to" block so the lab also sends the report
to the provider.
- Print — the ministry's own PDF, filled and flattened, previewed on the
page with Print / Download / Open buttons.
The form's own rules are enforced before anything prints: glucose needs Random
or Fasting; a hepatitis box needs Acute, Chronic or Immune status; PSA needs
Insured or Uninsured; Chlamydia, GC, Wound and Other Swabs need a specimen
source.
The signature box is always left empty. The PDF is unsigned; Dr. Latsky
signs by hand after review.
Running it
npm install
npm start # http://localhost:3000
npm run verify # form map vs. the ministry PDF, builder rules, end-to-end fill
npm run demo # writes out/demo.pdf
Node 18 or newer. One dependency, @cantoo/pdf-lib, which opens the
ministry's encrypted-with-an-empty-password form.
On Vercel
The repo deploys as-is: public/ is static and api/requisition.js is a
serverless function (vercel.json makes sure the PDF ships with it).
Changing the clinician block
config.js, or environment variables CLINICIAN_NAME, CLINICIAN_ADDRESS,
CLINICIAN_BILLING, CLINICIAN_CPSO, CLINICIAN_PHONE (urgent contact
number, blank by default). The browser cannot change it.
Layout
public/index.html the page
api/requisition.js GET: form description · POST: the filled PDF
config.js who it prints under
lib/form-map.js ministry PDF field names ↔ clinical meaning (ground truth)
lib/build.js ticked boxes + lines → plan, with the form's rules
lib/fill.js plan → filled, flattened PDF (one page per sheet)
lib/acroform.js load the encrypted blank, set states, flatten
lib/forms/on-4422-84.pdf the ministry's file, byte-for-byte
scripts/verify-forms.mjs every mapped field exists in the PDF
scripts/verify-build.mjs builder rules and a two-sheet render
form-map.js, fill.js and acroform.js are copied from the Orilume MD EMR's
lib/lab-requisition/ module. If the ministry reissues the form, re-derive the
map there and copy it over; verify-forms.mjs fails until it matches.
