Doubling Time
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Enter your PSA blood level to get
the PSA doubling time and velocity.
Date calendar
PSA ng/ml


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Comments from users
Your Name
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David 06-12-2011 04:41
Easy to use, But could not print the screen. Please fix. thanks
Dirk 14-11-2011 23:01
Hi, it's me again. Have 6th PSA number added and .... it is just lineair. Hypothesis does not work for now, maybe later, maybe never.
Dirk 22-09-2011 09:31
Great tool. You better know in advance where you stand.
Ted 22-08-2011 06:58
Nice to be able to get numbers to go by without all the "logarithmic" stuff
Hector 27-07-2011 18:06
Very informative,Now I understand doubling time
Tim 07-07-2011 15:11
Works good. I have to go back and get more blood work. I am 4.0 at 53 was 2.0 three years ago.
Phil 09-06-2011 20:25
It works great, but can`t seem to copy data?
hh 26-05-2011 20:56
thank you for offering this tool
T Mustin 13-05-2011 15:44
Very helpful--best one I've found.
CB 17-03-2011 16:19
Can't get this doubling info from my consultant. Thank you very helpful.
N Jansen 16-03-2011 18:49
Easy to use and quite helpful.
H.H. 17-02-2011 23:35
very helpful and easy to use. Thank you for the service.
JT 07-01-2011 23:30
Thanks for excellent tool. Better than my Doc seems to be able to do!
Awesome 25-09-2010 00:48
Another PSA calculator gives when the life threatening level of 4,000 would be reached according to the PSA which I think is easier for the average person to grasp. But your page is awesome.
FAQ
What is PSA?
PSA stands for Prostate Specific Antigen. PSA is producted by the prostate gland. PSA level often increases in case of prostate cancer, prostatitis and other prostate diseases.
How PSA velocity is calculated ?
PSA velocity was calculated as change from the first PSA reading, standardized as PSA change per month.
Given:
PSA1 : the first PSA reading
DT : the doubling time in month
V : the velocity
Then, V = PSA1 + 21/DT
What are the parameters of the formulas ?
Number of days in a year: 365.25
Number of days in a month: 365.25/12
I found sligthly different results elsewhere !
Curve fitting equations are used to fit your data to a theoritical curve. Several methods exist to do this job.
One method, first transforms your data into a line, then applies to this line the least squares fitting method. Another method (the one used here), applies least square fitting method directly to your data. This method was used because it weights the data points equally. You will find some explanations with an example plot here.

Weisstein, Eric W. Least Squares Fitting--Exponential. From MathWorld--A Wolfram Web Resource.
http://mathworld.wolfram.com/LeastSquaresFittingExponential.html .
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