No, a load study is not included in an appraisal.
An appraisal is nothing more than an estimate of market value for the property. It is not an inspection. A qualified home inspector should be able to tell you if the service is sufficient.
Unless you are planning to install some additional high electrical usage equipment in your garage/utility room 100 Amp service is certainly enough for your house, and current for today's standard.
BTW, How old is the home? Many homes built before WW-II may have 100 Amp Service coming into the house, but not enough outlets, insufficient wiring, etc? You may want the count the outlets per room. If you have only 2 per room, that is a bare minimum. You probably would want to add more. If this is the case, I would be more worried about the home having sufficient wiring, not the size of the incomming main service. If your house is this vintage, you should definately have a professional check the wiring out.
If you have a newer home (built 1970s or later) built to code, you probably have plenty of outlets, etc.
4 or more properly wired outlets per room would be preferred and should suffice if the are spaced in convienient locations.
There sould be at least 1 outlet per bathroom and these should have GFI protection.
In the kitchen, you need 4 or more outlets. Preferably on 2 or more seperate circuits. Any outlet within 6 feet of the sink should have GFI protection too.
Also be sure your outlets for the washing machine, or any outlet within 6 feet of water such as a utility sink has the GFI too.