diff --git a/Source/DelphiZXIngQRCode.pas b/Source/DelphiZXIngQRCode.pas
index 6f54de9..c13a1f5 100644
--- a/Source/DelphiZXIngQRCode.pas
+++ b/Source/DelphiZXIngQRCode.pas
@@ -1048,7 +1048,7 @@ function TEncoder.FilterContent(const Content: WideString; Mode: TMode;
     end else
     if (Mode = qmAlphanumeric) then
     begin
-      CanAdd := GetAlphanumericCode(Ord(Content[X])) > 0;
+      CanAdd := GetAlphanumericCode(Ord(Content[X])) >= 0;
     end else
     if (Mode = qmByte) then
     begin
@@ -3570,4 +3570,4 @@ procedure TDelphiZXingQRCode.Update;
   FColumns := FRows;
 end;
 
-end.
\ No newline at end of file
+end.