Most of the Mediclaim policies cover Renal / Kidney Transplant for recipient and donor. S few policies have conditions where only the recipient's medical expenses are covered.
The only condition for these policies is that the problem (renal failure or the cause for this) should not exist prior to policy start date as in that case it will fall under pre-existing disease (PED) category. In all PED cases, PED exclusions year coverage will apply.
In addition, there are Critical Illness coverage policies which also provide the coverage during specific conditions.
I would request you to contact general insurance companies for specific details on their policy benefits.