diff --git a/study/src/org/labkey/study/model/DatasetDataIteratorBuilder.java b/study/src/org/labkey/study/model/DatasetDataIteratorBuilder.java
index b93a586f5b3..5699d1e6a2a 100644
--- a/study/src/org/labkey/study/model/DatasetDataIteratorBuilder.java
+++ b/study/src/org/labkey/study/model/DatasetDataIteratorBuilder.java
@@ -713,7 +713,7 @@ public Object call()
                 assert null != indexPtidOutput || hasErrors();
 
                 String ptid = null == indexPtidOutput ? "" : getOutputString(indexPtidOutput);
-                sb.append(ptid);
+                sb.append(ptid.trim());
 
                 if (!_datasetDefinition.isDemographicData())
                 {