问题:
　　我的末次月经首日是8月13日，周期27-28天，规律，用排卵试纸监测LH水平，26日检测线与对照线出现，但LH未达峰值，27 28 29日却发现检测线已消失，于28日行房。请教专家LH水平是否于排卵日既已下降？我的受孕几率有多大？再有检测早孕试纸说受孕24H就可测出，是指房事后24H，还是受精卵着床后24H？

回答:
　　受精后。

English:Detection of early pregnancy test strip refers to when

Question:
my last first day of menstruation is August 13, cycle 27-28 days, the law, and LH ovulation test strip to monitor the level of detection on the 26th line with the control line, but LH below the peak, day 27 28 29 found that test line had disappeared on the 28th marital. Ask the Expert level of LH in the ovulation day has dropped? I have little chance of pregnancy? Detection of early pregnancy test strip and then have said that pregnancy can be detected 24H is room afterwards 24H, or a fertilized egg after implantation 24H?

answer:
After fertilization.