Have you ever wondered how your body magically stops a bleed? It’s not magic—it’s a highly coordinated “waterfall” of proteins known as Clotting Factors.
The trouble is, there are 13 of them (mostly numbered in Roman numerals), and they don’t always go in a logical order. To help you ace your next exam, we’re breaking down the most famous mnemonic in hematology.
The Secret Sentence
To remember the factors in order (I through XIII), just memorize this:
Foolish People Try Climbing Long Slopes After Christmas, Some People Have Fallen.
The Clotting Factor Breakdown
| Mnemonic Word | Factor | Common Name | Key Role |
| Foolish | I | Fibrinogen | The “glue” that forms the actual clot. |
| People | II | Prothrombin | Converts to Thrombin to activate Fibrin. |
| Try | III | Thromboplastin | Triggers the Extrinsic pathway (Tissue Factor). |
| Climbing | IV | Calcium | The essential mineral “bridge” for many steps. |
| Long | V | Labile Factor | A major accelerator in the common pathway. |
| Slopes | VII | Stable Factor | Part of the Extrinsic pathway. |
| After | VIII | Antihemophilic Factor A | Deficiency causes Hemophilia A. |
| Christmas | IX | Christmas Factor | Deficiency causes Hemophilia B. |
| Some | X | Stuart-Prower Factor | Where the intrinsic and extrinsic paths meet. |
| People | XI | PTA | Plasma Thromboplastin Antecedent. |
| Have | XII | Hageman Factor | Starts the Intrinsic pathway contact phase. |
| Fallen | XIII | Fibrin Stabilizing Factor | Cross-links fibrin to make the clot tough. |
Note: Factor VI is no longer considered a separate factor as it was found to be the activated form of Factor V.
Why Do We Need This Cascade?
The clotting process is like a series of falling dominoes. One factor activates the next in a massive amplification loop. If you are missing just one—like Factor VIII or IX—the whole system fails, leading to bleeding disorders.
Pro-Tips for Remembering
- The “Vitamin K” Group: Remember factors II, VII, IX, and X. These are Vitamin K-dependent. A quick way to remember these is the year 1972 (10, 9, 7, 2).
- The Common Pathway: Think of the “bills” ($1, $2, $5, $10). These are the factors involved once the pathways merge.