It's hard to resist taking a pregnancy test before one can reasonably expect a reliable result.
When seeing an early negative test result, most people wonder if they could still be pregnant and if they might test positive later on in the cycle. If a negative test was taken too early, the answer is most definitely, yes (Check the Chart Gallery for numerous examples) however it is still interesting to look at some statistical data about these pregnancy test results.
To explore the issue of the reliability of early pregnancy tests, we looked at just under 6000 charts for which a negative pregnancy test was followed by a positive test and did not result in a miscarriage.
First Negative Pregnancy Test Before Positive
Average: 9.08 DPO
Median: 9 DPO
First Positive Pregnancy Test After Negative
Average: 12.72 DPO
Median: 12 DPO
The first comment is that these charts belong to people who test more often than average. This explains why they tend to find they test positive slightly earlier than most (12-13DPO).