Dilutiontitrate 2 fold definition
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 Coral
 Posts: 260
 Joined: Tue Mar 21, 2006 9:33 am
Dilutiontitrate 2 fold definition
Hi there,
I have some sera and if it says "dilute sera in PBST (titrate 2 fold) starting at 1:200...what exactly does it mean...
I'm thinking say I start with a 1:200 1mL sample...take 5uL of sera and add 995uL of PBST..that would be my starting diltion right?..So titrating 2 fold would mean...?
Thanks in advance,
b_06er
I have some sera and if it says "dilute sera in PBST (titrate 2 fold) starting at 1:200...what exactly does it mean...
I'm thinking say I start with a 1:200 1mL sample...take 5uL of sera and add 995uL of PBST..that would be my starting diltion right?..So titrating 2 fold would mean...?
Thanks in advance,
b_06er

 Coral
 Posts: 167
 Joined: Fri May 19, 2006 1:47 am
My understanding is you do 1:200 then 1:100 then 1:50 then 1:25 then 1:12.5 and so on. The idea that I was taught when doing a 2 fold dilution is that you're diluting by a certain factor each time either 4 times, 3 times, or 2 times. That means taking that ratio and dividing by 2.
Your method of if you wanted 1000 uL as your final volume and removing 5 from 1000 and adding 5 of your sample is correct. You could do this for whatever final volume you want. For example a 1:200 dilution with a final volume of 600 uL would be 3 uL of sample into 597 uL of PBST. A 1:100 in 600 would simply be double that sample because you have altered by a factor of 2. So 6 into 594 uL.
Your method of if you wanted 1000 uL as your final volume and removing 5 from 1000 and adding 5 of your sample is correct. You could do this for whatever final volume you want. For example a 1:200 dilution with a final volume of 600 uL would be 3 uL of sample into 597 uL of PBST. A 1:100 in 600 would simply be double that sample because you have altered by a factor of 2. So 6 into 594 uL.
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