What Does An Atom REALLY Look Like? - Duration: 8:44. The Science Asylum 600,649 views
A NEGATIVE result from a Hemoccult II test means that there was no evidence of occult (hidden) blood detected in your stool specimen. However, this test is not a complete cancer detection examination; it only detects blood in the stool.
A positive blood group means that the person has Rh antigen on the red blood cells whereas a negative blood group means that the Rh antigen is absent on the red blood cells. Unlike ABO system, an Rh-ve person will not have anti-Rh antibody in the blood unless he/she has been previously exposed to Rh +ve blood.-negative blood group is the  universal donor  blood group. This means that a person with any blood group can receive O-negative blood. This is very important in emergency situations when a person requires immediate blood transfusion and there is no time to test his/her blood group.