diff --git a/MiabisOnFHIR/input/fsh/instances/collectionInstance.fsh b/MiabisOnFHIR/input/fsh/instances/collectionInstance.fsh
index 915cdc6..acf6324 100644
--- a/MiabisOnFHIR/input/fsh/instances/collectionInstance.fsh
+++ b/MiabisOnFHIR/input/fsh/instances/collectionInstance.fsh
@@ -38,7 +38,7 @@ Description: "example of a collection instance"
 
 * extension[numberOfSubjects].valueInteger = 100
 * extension[inclusionCriteria].valueCodeableConcept = InclusionCriteriaCS#HealthStatus
-
+* extension[MemberEntity].valueReference = Reference(Specimen/sampleId)