The word haemoproteid is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 21
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (65 words)
adepter, adopter, demerit, demirep, diether, dimeter, dimorph, diopter, dioptre, doormat, earthed, emirate, emptied, emptier, epiderm, epidote, epitome, etaerio, ethmoid, hardtop, headier, hearted, hemipod, homered, meatier, meatpie, mediate, merited, mitered, moodier, morphed, motored, operate, opiated, optrode, parotid, peatier, peridot, photoed, pirated, pithead, pothead, predate, preedit, preheat, premade, primate, promote, readmit, readopt, redtape, rehomed, remated, retaped, retimed, tapered, taproom, tearoom, tempera, tempore, tepider, theorem, torpedo, tramped, trooped