How Does Dual Health Insurance Work? 
I presume you are asking about a situation where a person has health insurance through their employer and is also covered as a dependent under their spouse 's or perhaps parent 's health plan . In these increasingly rare dual coverage situations a process called coordination of benefit applies . The general rule is that the person whose birthdate comes earliest in the year has the policy that it primary -LRB- first to pay onthe claim -RRB- and then the other policy pays in a secondary capacity covering what the primary policy has not paid -LRB- subject to the coverage terms of both policies -RRB- . In no case can the total amount paid by both policies exceed 100 % of the health claim amount . 