Question: how long after implantation are hcg levels high enough to test?
Answer: hCG levels are detected in the blood as early as 2-3 days, and in the urine 3-4 days, after implantation. A urine pregnancy test would be expected to be positive around the time of a missed period or 14-15 days after implantation (which can be as early as several days before a missed period).