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THE EIGHT BLOOD TYPES

1 / 3 · mockup · corridor-white

THE EIGHT BLOOD TYPES

three antigens, eight types — and the one rule the whole table of compatibility follows from

Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.

Three sizes in one archive — from a sheet on the fridge to a poster on the wall.

Premium$2.50

Payment and email are handled by Paddle. The download link arrives by email — no account, no password.

Formats
A4 · A3 · A2
What you get
Print-ready PDFs, one per size, with every letterform converted to outlines — nothing to install, nothing to shift.
Subject
science · reference · everyone · classroom

The diagram shows the rule the laboratory matches by: an arrow runs from a donor to anyone their red cells are safe for. In hospital, blood is cross-matched in the laboratory before every transfusion.

EIGHT, HALVED ONCE FOR EVERY ANTIGEN

Count your antigens and you know how many types you can give to: 8, halved once for each antigen you carry. O− has none and gives to all 8; O+ has one and gives to 4; A+ has two and gives to 2; AB+ has all three and gives to just 1 — itself.

Of all 64 donor-and-recipient pairings, 27 are safe — fewer than half. That is why the question "what type are you" comes before a transfusion rather than after it.

On the sheet

  • The diagram shows the rule the laboratory matches by: an arrow runs from a donor to anyone their red cells are safe for. In hospital, blood is cross-matched in the laboratory before every transfusion.
  • Colour carries meaning, but meaning never rests on colour alone — the sheet reads in black and white.
  • Nothing about how it was made: the sheet carries only what the reader needs.

Printing

  • Three sizes in the archive: A4 — 210×297 mm, A3 — 297×420 mm, A2 — 420×594 mm.
  • All text is converted to outlines. No fonts to install, and nothing shifts on another machine.
  • White background and sparing fills — it prints on a home printer without draining the cartridge.
  • Margins of at least 10 mm: a home printer cannot print to the edge.
  • No stroke thinner than 0.3 mm, so nothing disappears in print.

Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 7 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.

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