diff --git a/dstu3/src/main/java/org/opencds/cqf/dstu3/providers/ActivityDefinitionApplyProvider.java b/dstu3/src/main/java/org/opencds/cqf/dstu3/providers/ActivityDefinitionApplyProvider.java
index f4b2b7416..302b05c60 100644
--- a/dstu3/src/main/java/org/opencds/cqf/dstu3/providers/ActivityDefinitionApplyProvider.java
+++ b/dstu3/src/main/java/org/opencds/cqf/dstu3/providers/ActivityDefinitionApplyProvider.java
@@ -1,5 +1,6 @@
 package org.opencds.cqf.dstu3.providers;
 
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -147,7 +148,15 @@ private ProcedureRequest resolveProcedureRequest(ActivityDefinition activityDefi
         ProcedureRequest procedureRequest = new ProcedureRequest();
         procedureRequest.setStatus(ProcedureRequest.ProcedureRequestStatus.DRAFT);
         procedureRequest.setIntent(ProcedureRequest.ProcedureRequestIntent.ORDER);
-        procedureRequest.setSubject(new Reference(patientId));
+        String patientReferenceString = patientId;
+        URI patientIdAsUri = URI.create(patientReferenceString);
+
+        if (!patientIdAsUri.isAbsolute()
+                && patientIdAsUri.getFragment() == null
+                && !patientReferenceString.startsWith("Patient/")) {
+            patientReferenceString = "Patient/" + patientId;
+        }
+        procedureRequest.setSubject(new Reference(patientReferenceString));
 
         if (practitionerId != null) {
             procedureRequest.setRequester(
diff --git a/r4/src/main/java/org/opencds/cqf/r4/providers/ActivityDefinitionApplyProvider.java b/r4/src/main/java/org/opencds/cqf/r4/providers/ActivityDefinitionApplyProvider.java
index 9115197dd..799a33a94 100644
--- a/r4/src/main/java/org/opencds/cqf/r4/providers/ActivityDefinitionApplyProvider.java
+++ b/r4/src/main/java/org/opencds/cqf/r4/providers/ActivityDefinitionApplyProvider.java
@@ -1,5 +1,6 @@
 package org.opencds.cqf.r4.providers;
 
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -189,7 +190,15 @@ private ServiceRequest resolveServiceRequest(ActivityDefinition activityDefiniti
         ServiceRequest serviceRequest = new ServiceRequest();
         serviceRequest.setStatus(ServiceRequest.ServiceRequestStatus.DRAFT);
         serviceRequest.setIntent(ServiceRequest.ServiceRequestIntent.ORDER);
-        serviceRequest.setSubject(new Reference(patientId));
+        String patientReferenceString = patientId;
+        URI patientIdAsUri = URI.create(patientReferenceString);
+
+        if (!patientIdAsUri.isAbsolute()
+                && patientIdAsUri.getFragment() == null
+                && !patientReferenceString.startsWith("Patient/")) {
+            patientReferenceString = "Patient/" + patientId;
+        }
+        serviceRequest.setSubject(new Reference(patientReferenceString));
 
         if (practitionerId != null) {
             serviceRequest.setRequester(new Reference(practitionerId));