Make no mistake about it, you will lose blood here!  Over approximately 115 days, there are about 20 sticks total, almost always from the inner elbow, but once so far I've had vein trouble so they went to my outer-forearm.  Oddly, my left arm seems to pump better than the right.  It's usually pretty painless, the phlebotomists here are practiced and adept.
ClinLAB Clinical Laboratory Assessment + Urinalysis 5 times
Routine CBC (Complete Blood Count), plus blood chemistries, drug screening, Hermatocrit, Ferritin (iron levels) & ALT (liver enzymes).
ClinNutr Clinical Nutritional Assessment + Urinalysis 7 Times
In order to determine changes in muscle and bone, diet checks are constant.  All foods, fluids, medicines and test drugs ingested are weighed and recorded.  After certain "fasting" hours, blood will be drawn to examine levels of fluids, vitamins, minerals, etc. for a picture of total body make-up.
ImmC Immunocompetence 5 times
In order to examine the effect of bed rest on the body's natural response to "illness," blood is drawn and measured for stress hormones, immune system strength via antibody activity and overall ability to fight infection.
LVR Latent Virus Reactivation + Urinalysis + Saliva 5 times
Always pretty much the same stuff that the astronauts go through!  
In addition to these, all female subjects have two extra blood draws (during screening and during the initial ambulatory phase) to test for possible pregnancy.