Frequently being on the receiving end of Medlink's patients - my thoughts....
It is very difficult to diagnose a patient over a radio/phone link. Non medical personnel are notoriously bad at describing signs and symptoms and even relatively simple tasks such as taking pulses, blood pressures and recording respiratory rates require regular practise to be confident of an accurate result.
Many of the patients I/we see have completely different signs and symptoms and ultimately different illnesses/injuries to the Medlink diagnosis. This can result in avoidable diversions if a proper diagnosis is not made. However as has been said an un-necessary diversion is probably better for business than a dead passenger and the ensuing legal/
pr issues! No medical staff are going to ridicule you or complain about the call if you geninuely thought the pax was (dangerously/seriously) ill. (Call us out at 0400 for a crap job - Delhi belly for 3 days before boarding etc.... take your chance!)
I would say first ASK if there are any medically trained pax on board, who are willing to help - (varies between country again, but), most medical staff have a duty to treat a patient within their own skill level, to avoid negilgence claims.
Second choice has to be telemetry - if properly connected to the pax then its as good as a nurse/doctor/paramedic taking the observations.
Third would of course be Medlink.
Finally don't forget to ask the pax - they may actually know what's wrong with them, as may the travelling companions. Too often people call ambulances without asking the patient if they are actually ill!
PS. If you call an emergency ambulance to meet your flight PLEASE keep all the pax sat down in their seats until the ambulance crew are on board - its very difficult fighting your way through 300 people all trying to go the opposite way to you! Those of us who work at the airports regularly are aware of turnaround times and customer service issues particular to airlines and will make every effort to let you carry on as normal asap.
PW