simple blood tests to diagnose major diseases:

• Platelet distribution width: a simple, practical and specific marker of activity of coagulation.
• PDW, and not PC or MPV, as an independent predictor of all-cause and CV mortality.
• Platelet overactivation was frequently observed in CHF patients. Platelet overactivation may partly associate with the pathophysiology of adverse complications in CHF. PDW may be a novel and feasible prognostic marker for CHF patients.
• The inflammatory process in atherosclerosis may cause an increase in red blood cell distribution width (RDW) and platelet distribution width (PDW) values. 

what is platelet?thrombocyte; a disk-shaped structure, 2 to 4 μm in diameter, found in the blood of mammals and important for its role in blood coagulation; platelets, which are formed by detachment of part of the cytoplasm of a megakaryocyte, lack a nucleus and DNA but contain active enzymes and mitochondria.

• simultaneous increase of MPV ( mean platelet volume )and PDW (platelet distribution width) could reveal platelet activation.

• RDW-   (Red cell distribution width ),  fibrinogen, CRP, ESR, and platelet counts were all significantly elevated in patients having chronic inflammation.

• Red cell distribution width (RDW) could be a reliable index of anisocytosis with the highest sensitivity to iron deficiency.RDW to be the most significant indicator of active Ulcerative Colitis. For CrohnsDisease , CRP was an important marker of active disease.