Will the test work on old blood samples?

Blood samples stored at room temperature for 33 years have given positive results.

Please find more data in the validation study of the Seratec HemDirect by Dale L. Laux, Forensic Scientist at the Ohio BCI and Amanda Misencik:
Validation Study of the Seratec HemDirect Hemoglobin Assay for the Forensic Identification of Human Blood.