Can anyone explain my Navarro HCG test results?

Last October my test came back with a reading of Index + 4 (54.0 units). Test done last month came back with a reading of Index + 4 (52.2) which I gather is still in the slightly positive range - would this be right?

I'm also wondering just how reliable the Navarro test is? Any information would me much appreciated.

Thanks, Roger B
NZ