There are no such things as "healing ministries" in the New Testament. The only ministries set out are the Five Fold ministries mentioned in Ephesians 4:11.
Laying hands on the sick is for every believer, not just the 'superdupers" who are in it mainly to enhance their reputation and bank balance. Also, it is part of the role of church elder who is called upon by a sick person to be anointed with oil and have the prayer of faith said over him. Also, there are gifts of healing that can be manifested by any person in the body of Christ, and these are for the building up of the saints.
If a person purports to have a "gift of healing" which would support a "ministry of healing", then every person he prays for should be divinely healed. But, as we know, although great claims are made in mega-churches and large conferences of the healing that is supposed to happen, when the truth is known, very, very few are actually healed, and many of those are achieved by natural process or medical intervention.
In one big conference run by a "super-duper" who has since been exposed as an adulterous fraud, a whole lot of people were supposed to be healed, but when follow-up was done, none of them actually were, and one with terminal cancer who was told he was healed, died two weeks later!
If a person gets up and claims he has the "ministry of healing" then it can safely be said that he has nothing of the sort. The evidence of the manifestation of the gift of healing is that the sick person is instantly healed. This means if he had terminal cancer with a month to live, he could go back to his doctor, be xrayed and no trace of the cancer found. It is the same if a person has a Word of Knowledge about some with an illness, and prays for him, that person would have to be heal instantly for that Word of Knowledge to be from God and not just dreamed up out of the preacher's head.
I believe God heals and when He doesn't do it sovereignly, He uses ordinary "unknowns" to minister it to show that it is of Him and not through the claim of some self-style "superduper" who thinks he has something special that ordinary believers have no access to.