3 weeks late? The test should show positive by now.
Is she having any symptoms-Fatigue, bloating, breast tenderness, gas/burps, frequent urination? If she has irregular periods then she may not be pregnant. Keep a monthly diary to record when she gets her p's.May be she will find a pattern with the records and things will be more clear. Do a pregnancy test after 3-4 days. But use a good brand and follow instructions properly.Best to use early morning sample. If not dont drink any fluids for about 40 to 60 mins prior to taking the sample.the Control line should appear at all times. The test line..even if faint..indicates a pregnancy so tell her to go to the doc to get herself checked n be given vit n follic acid. If no test line appears, then Ur friend should still go to the doc to get herself checked.