I am 23 years old.A medical sdutent.Our department have a lot of blood serum and plasma of patient store in -80 degree in a refrigerator.Serum and plasma were in two tubes,and there is a tape outside the to connect these two tubes.Two days ago,we replace the tape using a scalpel.That scalpel cut the tape and then cut my hand,I squeeze the wound,there is some blood got out,not much,and then use the iodophor to clean the wound.Yesterday i found that serum and plasma was from an hiv patient.Serum and plasma was collected in 2013,3 years and a half past.I don not know if there is some blood spill out of the tube when they made these two tubes 3 years ago.I just know that there is no visible blood outside these tube,and no visible blood on the scalpel.I feel nervous now.I do not know if i got a chance to get HIV.