Javascript Disabled Detected

You currently have javascript disabled. Several functions may not work. Please re-enable javascript to access full functionality.

Am I doing my math right?

Started by mck_001 , Mar 25 2011 07:54 AM

Please log in to reply

6 replies to this topic

#1 mck_001

New Member

Members
0 posts

Posted 25 March 2011 - 07:54 AM

So, the PCR is 1,000,000 cells tested, right?

And the PCR is a percentage, right?

If so, a PCR of 1.14 means there are 8,772 cancer cells found within those 1,000,000 cells.

Or is that not at all how the PCR is related to the 1 million cells. LOL!

I love that I have people like y'all who really understand all of this stuff to bounce all of my crazy questions to!

*Edited to add: I really don't expect that it is this simple. LOL! But, obviously, I'm still not getting the PCR and the scales and how it all works.

Back to top

#2 CallMeLucky

Advanced Member

Members
216 posts

LocationCT

Posted 25 March 2011 - 09:23 AM

Hi MK you should check out this video, it does a very good job of explaining how PCR works relative to CML

http://www.youtube.c...h?v=ZwgynKh6J5U

Date - Lab - Scale - Drug - Dosage MG - PCR

2010/Jul - MSKCC - Non-IS - Gleevec - 400 - 1.2%

2010/Oct - MSKCC - Non-IS - Gleevec - 400 - 0.25%

2010/Dec - MSKCC - Non-IS - Gleevec - 400 - 0.367%

2011/Mar - MSKCC - Non-IS - Gleevec - 400 - 0.0081%

2011/Jun - MSKCC - Non-IS - Gleevec - 400 - 0%

2011/Sep - MSKCC - Non-IS - Gleevec - 400 - 0.00084%

2011/Dec - MSKCC - Non-IS - Gleevec - 400 - 0%

2012/Mar - MSKCC - Non-IS - Gleevec - 400 - 0.004%

2012/Jun - MSKCC - Non-IS - Gleevec - 400 - 0%

2012/Sep - MSKCC - Non-IS - Gleevec - 400 - 0%

2012/Dec - MSKCC - Non-IS - Sprycel - 100 - 0%

2013/Jan - Quest - IS - Sprycel - 50-60-70 - 0%

2013/Mar - Quest - IS - Sprycel - 60-70 - 0%

2013/Apr - CUMC - Non-IS - Sprycel - 50 - 0.036%

2013/May - CUMC - Non-IS - Sprycel - 50 - 0.046%

2013/Jun - Genoptix - IS - Sprycel - 50 - 0.0239%

2013/Jul - Genoptix - IS - Sprycel - 70 - 0.0192%

2013/Jul - Genoptix - IS - Sprycel - 70 - 0.0034%

2013/Oct - Genoptix - IS - Sprycel - 70 - 0.0054%

2014/Jan - Genoptix - IS - Sprycel - 70 - 0.0093%

2014/Mar - Genoptix - IS - Sprycel - 100 - 0.013%

2014/Apr - Genoptix - IS - Sprycel - 100 - 0.0048%

2014/Jul - Genoptix - IS - Sprycel - 100 - 0%

2014/Nov - Genoptix - IS - Sprycel - 100 - 0.047%

2014/Dec - Genoptix - IS - Sprycel - 100 - 0%

2015/Mar - Genoptix - IS - Sprycel - 100 - 0%

2015/Jun - Genoptix - IS - Sprycel - 100 - 0%

2015/Sep - Genoptix - IS - Sprycel - 100 - 0%

2015/Dec - Genoptix - IS - Sprycel - 100 - 0%

2016/Mar - Genoptix - IS - Sprycel - 100 - 0.0228%

2016/Jun - Genoptix - IS - Sprycel - 100 - 0%

2016/Sep - Genoptix - IS - Sprycel - 100 - 0%

2016/Dec - Genoptix - IS - Sprycel - 100 - 0%

2017/Mar - Genoptix - IS - Sprycel - 100 - 0%

2017/Jun - Genoptix - IS - Sprycel - 100 - 0%

2017/Sep - Genoptix - IS - Sprycel - 100 - 0%

2017/Dec - Genoptix - IS - Sprycel - 100 - 0%

Back to top

#3 Trey

Advanced Member

PS Beta Group
1,705 posts

LocationSan Antonio, Texas

Posted 25 March 2011 - 10:27 AM

Sorry, but none of the premises are right. PCR is a method of estimation of the quantity of some type of gene sequence (for CML it is BCR-ABL) based on measuring for that certain gene sequence under forced rapid cell growth conditions. Although the results are expressed as a percentage, they do not mean you have X percent leukemic WBCs in the body. Only a BMB and FISH give an actual (well, close enough) percentage of leukemic WBCs in the body.

The 1 in 1 million you refer to is the sensitivity level of the PCR test. If there is 1 leukemic cell for every 1 million good cells in the sample being tested, it should be able to detect it. If the sample has fewer than 1 in 1 million leukemic cells, then the sample should be PCR undetectable (PCRU).

Back to top

#4 PhilB

Advanced Member

Members
130 posts

Posted 25 March 2011 - 12:11 PM

The one that's got me foxed is how you came up with 1.14% of 1 million being 8,772 rather than 11,400 ?

As Trey says the genetic material in your sample is put through a period of 'forced growth' (basically they put the samples in a test tube, ply them with drink, put on some Barry White and wait for them to get reproducing) The PCR then measures the ratio of two different markers in what results and expresses that as a percentage. It's a bit like saying we don't know how many people on this site wear hats and we don't know how many have the sharts, but the ratio is 114 hat-wearers to every 10,000 shart-sufferers.

Phil

Back to top

#5 hannibellemo

Advanced Member

Members
728 posts

LocationNorth Central Iowa

Posted 26 March 2011 - 07:57 AM

Phil,

I find the fact that your analogies make perfect sense to me quite frightening!

Pat

"You can't change the direction of the wind but you can adjust your sails."

DX 12/08; Gleevec 400mg; liver toxicity; Sprycel 100mg.; CCyR 4/10; MMR 8/10; Pleural Effusion 2/12; Sprycel 50mg. Maintaining MMR; 2/15 PCRU; 8/16 drifting in and out of undetected like a wave meeting the shore. Retired 12/23/2016! 18 months of PCRU, most recent at Mayo on 7/25/17 was negative at their new sensitivity reporting of 0.003.<p>

Back to top

#6 Guest_billronm_*

Guests

Posted 26 March 2011 - 01:41 PM

Dear Pat,

As soon as I find my wine we definitely have to have a party at Phils House. Can you imagine the conversations that would take place? We have invented our own language, and have a soap opera on the way to chapter 2.

LOL BILLIE

Back to top

#7 mck_001

New Member

Members
0 posts

Posted 26 March 2011 - 02:56 PM

Obviously, I was in need of some better explanations...thanks, gang!!

And, Phil...the truth is after taking my GRE, I completely wiped my brain of all math above a 2nd grade level. I don't know if I ever really figured out how to find percentages from decimals...though...that always confused me.

But, instead of blaming my bad math on myself, I'd rather blame it on the TKIs as an annoying side effect of Sprycel.

Glad you are all my BIF's instead of in real life friends, or I may be embarrassed by my poor math and grammar on this board...but probably not. Ha!