New Delhi, Oct. 26 -- Most insurance policyholders believe that once they are admitted to a hospital, the insurer will pay the bills. However, health insurance policy documents often include a "reasonable and customary" clause, which allows insurers to pay only for costs that they consider fair and standard.

Insurers can assess whether a treatment, its cost and the number of days spent in hospital were actually necessary.

Most claims pass smoothly through these filters, but for those that are rejected, the clause proves to be a primary reason, second only to declines due to pre-existing health conditions.

Patient's pain

Take the case of this driver living in a tier-two town who had gastroenteritis. The local hospital, which was on the...