A test kit for preparing a chemical test pad used in testing for {HEAD ~ the presence} of {TAIL ~ occult blood} in a specimen 
A test kit for preparing a chemical test pad used in testing for { HEAD ~ the presence } of { TAIL ~ occult blood } in a specimen
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH