**1) How to prepare and Aliquot of Cholinesterase Reagent???**

  -  Dissolve R1 in 30 ml and R2 in 1 ml of QC water.
  -  Mix R1 and R2 after 15 min when there is complete dissolving of R1 and R2.
  -  Aliquot 1.5 ml of reagent in plain vaccutte after proper washing of vaccutte.
  - (For washing of plain vaccutte, use DI water, dry it all vaccutte then use it.)
  -  Keep frozen these vaccutte in deep freeze No. 16.
  - Use 1 vaccutte of reagent as and when required.
  -  Preserve the residual reagent after use in same deep freeze mentioned above.

**
2) How to Prepare Test Sample ????**

  - Linearity of method is very low and normal serum OD is high so we are using dilutedsample for estimation of CHE.
  -  In Randox Kit litrature, they are suggesting 1⁄2 dilution of test sample.
  - In Our Laboratory, we are using five times diluted test sample.
  -  For this purpose, take 400 micro lit of DI water and add 100 micro lit of test sample. And mix it well.
**
3) When and How to do Calibration of CHE Reagent???**

  - Do Calibration when new lot of reagent come in use.
  - Prepare one one cup of Cal-2, Cal-3, QC-5 and QC-8 as test sample.
  -  Take take 400 micro lit of DI water and add 100 micro lit of test sample. (Here Cal-2, Cal-3, QC-5 and QC-8). And mix it well.
  -  Also Run one cup of Blank as test sample.
  - Set Sample Replicate “4” in Erba XL 640. Run all these five Test Samples. Take 4 ODs from each test sample.
  -Prepare Calibration File and Get calibration Factor, Feed this factor in Erba XL 640, And Use this Factor.

**4) How to do QC on Daily Base???**
  - Prepare one level of QC as test sample and run along with when sample come.