blood test

Two children were sitting outside a clinic. One of them was crying
very loudly.
2nd Child: Why are you crying?

1st Child: I came here for a blood test.

2nd Child: So? Are you afraid?

1st Child: No. For the blood test, they cut my finger.

At this, the second one started crying profusely.

The first one was astonished.

1st Child: Why are you crying now?

2nd Child: I came for a urine test !