Two children were sitting outside a clinic...

Two children were sitting outside a clinic. One of them was crying.
1st Child: Why are you crying?
2nd Child: I came here for a blood test.
1st Child: So? Are you afraid?
2nd Child: No. For the blood test, they cut my finger.
At this, the first one started crying profusely.
The second one was astonished.
2nd Child: Why are you crying now?
1st Child: I came for a urine test!