Coolant = Antifreeze. A Shop With A Cooling System Pressure Tester Can Do It. Most Shops Should Have One. They Are Relatively Inexpensive.
The shop attaches a little pump to your cooling system and pumps it up to the pressure that cooling system is designed to operate under. A gauge will indicate that the system can hold pressure over time. A drop in pressure indicates a leak and often makes the location of the leak obvious.
Water pumps, pressure caps, freeze plugs, radiators, hoses, heater cores, and gaskets are some of the places coolant can leak. Some leaks are inexpensive to fix and some not. Somes leaks are external and drip on the floor. Some leaks are inside the engine, often caused by faulty intake manifold or cylinder head gaskets.
This does need to be taken care of before damage results. A small leak can turn into a big leak without warning and the posssibility of overheating or contaminated engine fluids exists.