Time

In saline phases most blood group antibodies will react optimally between 30-60 minutes, thus this is the usual incubation period that is used. If too short an incubation period is used, false negatives can result as enough Ag.Ab complex will not have formed. Likewise, too long an incubation period can cause false negatives as k₂ may overtake k₁ (from the law of mass action).

When LISS, polyethylene glycol (PEG), gel, red cell affinity column technology (ReACT), and solid phase immune adherence (SPAA) methods are used, antibodies become detectable within 15 minutes.

Time