Let's talk about this "HPT accuracy chart"
Jan 23, 2015 14:35:44 GMT -5
Post by getzystark on Jan 23, 2015 14:35:44 GMT -5
So this "HPT accuracy chart." I have no idea where that came from or what level of HCG they are saying the HPTs are measuring. It's probably an average of 10-100mIU. It's also probably taking into account an "average" LP of 14 days.
Wondfos (and a lot of other HPTs) don't actually print what mIU they are, likely because it could vary. A website (*yak*countdowntopregnancy*yak*) stated they were a 25 mIU test, but I have heard many women say that they have gotten positives (extremely faint) with a blood level of 7 mIU. However blood HCG concentration =/= urine. Same with the FRERs and they don't post their mIUs either, but it's likely as close as 10 mIU.
Anyway...that chart is grossly off if you're using a test that detects 10 mIU or even up to 25mIU of HCG in the urine. The accuracy would be what is posted on the FRER website. It is probably taking into account that on "average" the egg implants at 9dpo with an average female's hcg level in their urine being 5 mIU or less. Doubling time would give you a result of 10 mIU by 11dpo on average. Again, the charts have to use averages, so therefor the percentages take into account shorter or longer LPs and different implantation times.
NUMBER OF DAYS BEFORE THE EXPECTED PERIOD/% OF SAMPLES FROM PREGNANT WOMEN GIVING A POSITIVE RESULT
1 >99% (14dpo)
2 >99% (13dpo)
3 >99% (12dpo)
4 96% (11dpo)
5 76% (10dpo)
ALSO. LP length DOES NOT determine when you implant.
If you have a 10 day LP, your likelihood of having a "false negative" is higher because that egg implants only 3 days before your "missed period" vs someone with a 15 day LP.
Can we have a discussion regarding accuracy of HPTs and DPO testing. Please let me know if there's something I have wrong or I've left out. I welcome research and articles that you guys have found!
Edit: I fixed my dpos on the chart. Taking into a 14 day LP, not a 13 day.
Wondfos (and a lot of other HPTs) don't actually print what mIU they are, likely because it could vary. A website (*yak*countdowntopregnancy*yak*) stated they were a 25 mIU test, but I have heard many women say that they have gotten positives (extremely faint) with a blood level of 7 mIU. However blood HCG concentration =/= urine. Same with the FRERs and they don't post their mIUs either, but it's likely as close as 10 mIU.
Anyway...that chart is grossly off if you're using a test that detects 10 mIU or even up to 25mIU of HCG in the urine. The accuracy would be what is posted on the FRER website. It is probably taking into account that on "average" the egg implants at 9dpo with an average female's hcg level in their urine being 5 mIU or less. Doubling time would give you a result of 10 mIU by 11dpo on average. Again, the charts have to use averages, so therefor the percentages take into account shorter or longer LPs and different implantation times.
NUMBER OF DAYS BEFORE THE EXPECTED PERIOD/% OF SAMPLES FROM PREGNANT WOMEN GIVING A POSITIVE RESULT
1 >99% (14dpo)
2 >99% (13dpo)
3 >99% (12dpo)
4 96% (11dpo)
5 76% (10dpo)
ALSO. LP length DOES NOT determine when you implant.
If you have a 10 day LP, your likelihood of having a "false negative" is higher because that egg implants only 3 days before your "missed period" vs someone with a 15 day LP.
Can we have a discussion regarding accuracy of HPTs and DPO testing. Please let me know if there's something I have wrong or I've left out. I welcome research and articles that you guys have found!
Edit: I fixed my dpos on the chart. Taking into a 14 day LP, not a 13 day.