diff --git a/schemas/med_dossier/Measurement.yaml b/schemas/med_dossier/Measurement.yaml
index 1a6df1b..9586328 100644
--- a/schemas/med_dossier/Measurement.yaml
+++ b/schemas/med_dossier/Measurement.yaml
@@ -4,6 +4,12 @@ required:
   - when
   - value
 properties:
+  wcia:
+    description: |-
+      NHG-standardized WCIA (Werkgroep Coördinatie Informatie Automatisering) code (describes the nature of the measurement),
+      as listed on [Webtools NHG labcodeviewer](https://bepalingen.nhg.org/labcodes/determinations), under column 'Nr.'.
+    type: number
+    example: 1872
   code:
     description: |-
       NHG-standardized labcode (describes the nature of the measurement), as listed on