my last period was Dec. 9 2014. Took a test Jan 4th and got a positive, they did blood test Jan 5th and my levels were 102. and then a few days later (on Friday jan 9th) they were 500.
Since I have taken out my birth control yes my Pired are very regular. but I did just get my birth control taken out in October
Transvaginal not transnational..*
So in general, your hcg levels are first detectable by blood test 11-12 days after the egg has been fertilized. and about 2 weeks by urine test. Your levels should double about every 60-72 hours and sac should then be visible on transnational ultrasound once your levels reach 1-2 thousand. Your levels are still so low, that they can't put a date on it until you have another test done to see how much they have gone up. 1 week is incorrect because the levels won't even show in a blood test until almost 2. If you take a pregnancy test and it's positive you should assume your at least 2-3 weeks. A non pregnant woman's hcg levels are 5. Just have to wait and see!
You can't really be 1 week pregant, week 1 is really 2 weeks before you have sex, when you conceive you are already 2 weeks and by the time your period is due your already 4 weeks, that's if you ovulate normally with a 28 day cycle, are you normally pretty regular with your periods?
That does seem low for 4 weeks
That's really low to be 4 weeks