DNS Healthcare Links Page
Medical Links: (most go directly to provider login screen) Resources There:  

Cigna

Claim Status, Eligibility, Referrals
United Healthcare
Claim Status, Eligibility
GEHA
Claim Status, Eligibility
THIN (Clearinghouse)/ Ecare
Claim Status, Eligibility
(BC/BS, Aetna, Cigna, Humana)