# Trying to determine %Recovery with Custom Fields

Hello!

I'm new to custom fields and have been trying my best to reverse calculate based on what my predecessors at my company have done. We are trying to determine a %recovery based on amounts obtained. We have a linear regression which gives us an amounts value for our 5 RSD standards and control standards. Want to determine %Recovery based on these amounts. Currently this is the formulas I have been working with:

Name Calc

A_Bracket_Std_EDTA C1%.%.%(Amount)

B_Avg_Std_EDTA S101.%.%.AVE(Amount)

C_Percent_Recovery_EDTA (A_Bracket_Std_EDTA/B_Avg_Std_EDTA)*100

and at the end to show pass/fail

D_Percent_Agreem_Check_Crit

RANGE([C_Percent_Recovery_EDTA_Cont],98.0, 102.0)

I feel that I have something incorrect in the A or B function but I unsure what that would be.

Any help would be great!

I'm new to custom fields and have been trying my best to reverse calculate based on what my predecessors at my company have done. We are trying to determine a %recovery based on amounts obtained. We have a linear regression which gives us an amounts value for our 5 RSD standards and control standards. Want to determine %Recovery based on these amounts. Currently this is the formulas I have been working with:

Name Calc

A_Bracket_Std_EDTA C1%.%.%(Amount)

B_Avg_Std_EDTA S101.%.%.AVE(Amount)

C_Percent_Recovery_EDTA (A_Bracket_Std_EDTA/B_Avg_Std_EDTA)*100

and at the end to show pass/fail

D_Percent_Agreem_Check_Crit

RANGE([C_Percent_Recovery_EDTA_Cont],98.0, 102.0)

I feel that I have something incorrect in the A or B function but I unsure what that would be.

Any help would be great!

0

## Answers

Next, i would swap around the names of the CFs as your third one is asking Empower to divide an intersample CF with an intersample summary CF, the result of which doesnt exist until Empower reaches the Summarize Custom Fields line, where it travels back up to the top of the sample set and searches for a label called S101, and proceeds to average peak amounts for all injections with this label. Empower processes sample sets line by line, and at line labelled C1..etc, it doesnt yet have the average amount result, therefore it cannot execute your first custom field. Change the name of your second CF to A_avr_std_EDTA and your first CF to B_bracket_std_EDTA.

Then change the formula of the third CF to:

(B_bracket_std_EDTA*100)/A_avr_std_EDTA but you can still call it C_percentrecovery_EDTA.

Be aware that your 4th CF wont include any values of 98.0. RANGE in Empower means GT X and LTE Y. For example RANGE(Area,1000,10000) will return true for any areas greater than 1000 and less than or equal to 10000. If you want your 4th CF to work you need to tell Empower to round your range values to 1 decimal place and subtract 0.1 from your X value in order for Empower to include all values between 98.0 and 102.0, so values from as low as 97.95 up to 102.04. Change the Bool formula to:

RANGE(ROUND(C_percentrecovery_EDTA,-1),97.0,102.0)

Hope this helps.

That's very strange, I created similar CFs in a test project using the same sequence of standards and controls etc and I got values for them. The only differences I see is I didn't use % for the channel part of the syntax, so S101.%..AVE(Amount) plus I didn't specify for controls amount like you did in your first CF, I had 3 CFs, first one was S101.%..AVE(Amount), second was (Amount*100)/Average_Amount (which will include amounts for control samples) and then RANGE(Second_CF,98,102), and it worked out fine for me.

Are you getting any amounts at all for the 5 working standards? Maybe double check your processing method and component editor that names are spelled correctly, the correct processing method was used to calculate amount, you have the right search order (Result Set Only). It is possible to do since I did it, so it must be something small that's blocking your progress.

#1 Your std curve is generated appropriately.

#2 The processing method used for calibration and quantitation is the exact same method for all injections.

#3 When processing, you flag the calibrate and quantitate drop down and check box.

#4 The amounts are entered into the component editor in the sample set, not the PM.

#5 Each level in the component editor is spelled exactly as it is in the PM and exactly the same for each line in the component editor.

I realize these may seem obvious, but they are the critical pieces needed to generate an amount.

Just to add, if you are getting accurate amounts for the 5 working standards and the controls, then there isn't an issue with amount. The issue is in the CF used to average them, so S101.%..AVE(Amount). This is the only source of error left- are you absolutely sure the label is identical to the formula? is it S101 and not S1O1 (the letter O)? Is there a gap in the label somewhere?

Do you process sample sets using Result Set Only? Result Set First and Outside First give strange values when using intersample CFS. Is there enough tablespace left in the project? Is the Summarize Custom Fields set to Normal processing and nothing in the label reference? The only thing it could be is something in that formula. if you can get an average value for amounts using a report method, you should be able to get it with that CF too.

Is it just the report method that isn't showing any entries or is it still blank in the result set when you cycle through all the injections? If there is a value for Average Area in the result set but not the report, then the wrong custom field was inserted into the report. Or the report could be corrupt, test a new table and insert the average std CF and see if it works.