What to do to confirm? :
Both Urine and Serum
beta HCG comes positive as soon as u miss the period.
Urine
pregnancy test: It shows Urine concentration of Beta HCG hormone, which may vary with the Time of urine collection, Quality of test kit and Concentration of HCG in urine.
Serum Beta HCG: Which is confirmatory test for pregnancy. It is blood concentration of Beta HCG hormone and doesnt affect by above factors.