diff --git a/src/DataStructures.cpp b/src/DataStructures.cpp
index 09f59007..c27d33e7 100644
--- a/src/DataStructures.cpp
+++ b/src/DataStructures.cpp
@@ -463,7 +463,7 @@ std::string get_input_pair_long_desc(int pair)
 
 TEST_CASE("Check that all parameters are descibed","")
 {
-    for (int i = 0; i < CoolProp::iundefined_parameter; ++i){
+    for (int i = 1; i < CoolProp::iundefined_parameter; ++i){
         std::ostringstream ss;
         ss << "Parameter index," << i << "last index:" << CoolProp::iundefined_parameter;
         SECTION(ss.str(), "")