diff --git a/public/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/SamplesTsvToJson.scala b/public/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/SamplesTsvToJson.scala
index ff31439d9f0622ef73e3386e207971caa715a607..ac5a8bfbde5ccaae0156a4249ba26a86b59ae3a7 100644
--- a/public/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/SamplesTsvToJson.scala
+++ b/public/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/SamplesTsvToJson.scala
@@ -71,7 +71,7 @@ object SamplesTsvToJson extends ToolCommand {
       val library = if (libraryColumn != -1) Some(values(libraryColumn)) else None
 
       //FIXME: this is a workaround, should be removed after fixing #180
-      if (sample.head.isDigit || library.forall(_.head.isDigit))
+      if (sample.head.isDigit || library.exists(_.head.isDigit))
         throw new IllegalStateException("Sample or library may not start with a number")
 
       if (sampleLibCache.contains((sample, library)))