children interact and play with the expert of Animal Assisted Intervention (AAI) and his/her trained dog in the waiting room and then, are accompanied by a parent (as standard care) and the AAI in the venipuncture room during and immediately after the procedure

children interact and play with hospital clowns in the waiting room and then, are accompanied by a parent (as standard care) and the clown in the venipuncture room during and immediately after the procedure

children interact and play with a musician in the waiting room and then, are accompanied by a parent (as standard care) and the musician in the venipuncture room during and immediately after the procedure

children are accompanied by a parent in the waiting room and then in the venipuncture room during the procedure, thus receiving standard care

Operators of AAI and their dog meet the child and his/her parent in the waiting room and facilitates interaction using their professional characteristics. The interaction continue in the venipuncture room during the procedure and at its conclusion; in fact, the operators accompany the child and his/her parent outside the venipuncture room, to not abruptly interrupt the interaction.

Brief Behavioral Distress Scale - BBDS is an observational measure that assess children's procedure-related distress with 12 discrete component steps involved in venipuncture, in order to observe specific demands for compliance on the child during the procedure. Observers record the occurrence or nonoccurrence of the target behaviors during each step. Operational definitions of the target behaviors for each category are: 1) Non interfering Distress Behaviors; 2) Potentially Interfering Distress Behaviors; 3) Interfering Distress Behaviors. The number of steps in which a behavior occur is summed and divided by the total number of steps, then multiplied by 100 to yield percentage of steps with occurrence scores for each behavioral category. The number of steps in which behaviors from any of the three distress behavior categories occur is summed and divided by the total number of steps multiplied by three, then multiplied by 100 to obtain the Total Distress Score.

Numerical scales, based on age, Wong Baker Scale. The Wong Baker Faces Pain Rating Scale (Wong & Baker, 1998) is a self-report scale for children older than 3 years old, that shows a sequence of faces ranging from a happy face at 0 level, that means "No hurt", to a crying face at 10th level, that means "Hurts worst".

Numerical scale, Visual Analogue Scale - VAS. VAS is used from the age of 7 years old, is a self-report numerical scale ranging from 0, that means "No pain", to 10, that means "worst pain".

Self-report scale (State-Trait Anxiety Inventory - STAI). The STAI is a self-report anxiety behavioral instrument for adults. It consists of two separate subscales: one assessing trait anxiety (baseline, Y1), the other assessing the state anxiety (situational, Y2). Each subscale is composed by 20 items, rated on a 4-points Likert scale and separately analyzed. Total score for each subscale range from 20 to 80, with higher scores denoting higher levels of anxiety.