My wife got faint positive line(clearly visible on casual look) hpt on 1st day of missed period(day31 lmp).shld we consult doc immediately or post 1wk?

Depends: It depends on how fast you wish to have an answer. A blood test for HCG level usually provides definitive result at one day after a missed period. If you have patience, you may repeat the home test in 3-4 days. Use first morning urine and follow the instructions for the test carefully. The lady should see a doctor if she is trying to be pregnant and take pre-natal vitamins.