diff --git a/docs/site/reference.md b/docs/site/reference.md
index 579f4523..df92377b 100644
--- a/docs/site/reference.md
+++ b/docs/site/reference.md
@@ -15,14 +15,6 @@ linkage evaluation phase. The following features are supported:
 
 :   The patient's birthdate (normalized to `YYYY-MM-DD`).
 
-`MRN`
-
-:   The patient's medical record number.
-
-`SSN`
-
-:   The patient's social security number.
-
 `SEX`
 
 :   The patient's sex (normalized to `M`, `F`, or `U` for unknown).