CALIBRATION ACT DIFF2 ANALYZER

Effective Date: 
Sun, 04/01/2012
Reviewed: 
Tue, 01/10/2017
Revised: 
Fri, 08/16/2013
Policy: 

 

Principle

Calibration is the procedure used to standardize the instrument for accuracy by determining the instrument’s deviation from calibration references and applying necessary calibration correlation factors. These factors allow fine tuning of the instrument for accuracy.

Because the instrument is electronically stable, it should not require frequent recalibration under normal conditions of use.  Make the decision to recalibrate based on the performance of the AcT diff2 analyzer quality‑control program:  verify that 95% of control results are within the correct ranges and there are no unexplained shifts or trends in the data.

 

Materials, Controls and Calibrator 

COULTER 4C PLUS cell control: abnormal low, normal and abnormal high. COULTER S‑CAL calibrator.

Control/Calibrator Preparation

Handle controls and calibrators using universal precautions. Controls and calibrator contain stabilized human erythrocytes and no test method can offer complete assurance that Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), Hepatitis B Virus (HBV) or other infectious agents are absent. Take appropriate safety measures to avoid contact from aerosols when removing the cap/stopper assembly.

Allow refrigerated controls/calibrators to reach room temperature before use. Mix by hand according to directions in the technical insert accompanying the product.

Control/Calibrator Storage

Store at 2-8C (35-46F). Sealed control and calibrator vials are stable until the expiration date. Opened calibrator vials are stable for 1 hour.  Discard expired control/calibration materials.

Before use, inspect controls/calibrators for indications of instability or deterioration. Gross hemolysis (darkly colored supernatant) is indicative of product deterioration. Do not use deteriorated product.

Procedure: 

 

Calibration Procedures 

Calibration Frequency

Calibrate at least once every six months or after replacing major components that involve the primary measurement characteristics (such as an aperture) or when control values are consistently out of expected assay range. Coulter calibrates the AcT diff2 Analyzer at the factory before shipment. Always verify calibration by running 3 levels of controls immediately after calibrating.

If recalibration appears necessary, but a component affecting calibration was not replaced, do NOT recalibrate the instrument. First, ensure that all required maintenance (including replacement of parts) was performed on the instrument. Then thoroughly clean the AcT diff2 analyzer following the "Clean Baths" procedure in Chapter 6 of the Operator's Guide.  Reanalyze a new vial of control material. If the control results are still outside of the expected ranges, refer to pages 6-81 and 6-91 of the Operator's Guide for corrective action.  If this does not solve the problem, call your Beckman Coulter Representative before recalibrating.

Before you begin calibration, be sure you have enough reagents to perform the complete procedure.  If you run out of reagents during calibration, you must start over and perform a complete calibration.

Before calibrating, you must first prepare the instrument by doing the Precalibration Checks, Reproducibility and Carryover Checks.
 

 Precalibration Checks

  1. Be sure that all required maintenance (including replacement of parts) has been performed on the instrument.  See the Special Procedures and Troubleshooting section of the AcT diff2 Operator's Guide.
  2. Do the "Clean the Baths" procedure found in Chapter 6, page 4 of the AcT diff2 Operator's Guide.
  3. Calibrate only when the ambient temperature is within the system's operating range    (20°‑25° C).
  4. Check that you have a sufficient supply of reagents to complete this procedure.
  5. Perform Startup.

Reproducibility Check

Reproducibility is a check to ensure that the instrument measures blood parameters consistently and precisely.  After you run the sample N times consecutively, the instrument: calculates the Standard Deviation (SD) and the Coefficient of Variation (%CV), and prints PASS or FAIL for the reproducibility test.
It is recommended that you run Reproducibility in the Whole Blood Mode, using either whole blood or 4C Plus cell control.

When doing Reproducibility, Carryover or Calibration, do not leave the screen until you finish analyzing the required number of samples.  Leaving the screen without finishing the required analysis will delete your data, which means that you must restart the test.

  1. Select a sample that meets these parameter criteria:

            WBC at 6.0 ‑ 15.0 x 103 cells/ L                                                      

            RBC at 3.00 ‑ 6.00 x 106 cells/ L                                                     

            Hgb at 12.0 ‑ 18.0 g/dL                                                                                

            MCV at 80.0 ‑ 100.0 fL                                                                 

  Plt at 200 ‑ 500 x 103 cells/ L                                                           

  1. At the Main screen, select the desired mode to run normal whole blood samples or 4C PLUS cell control.
  2. At the Main screen, touch the QA icon.
  3. At the QA screen, touch the Reproducibility icon.
  4. Analyze the sample based on the mode you selected in step 2.
  5. When the sample result is displayed, touch the Trash icon to manually delete the first (prime) sample.
  6. Repeat step 5 until an N of 10 is achieved.  Look at the upper left corner of the screen for the N#.  After the instrument accepts the data, the Reproducibility results are stored.
  7. If you are using a graphic printer, touch the Print Summary icon. Keep a copy of the Reproducibility Summary Report in the hematology QC binder for your records.
  8. If any parameters FAIL, call your local Beckman Coulter Representative.

Carryover Check

Carryover is a check to make sure that no part of a sample is carried over to the next sample, thus affecting the next sample’s results.  Carryover determines if there is carryover from the sample and prints PASS or FAIL for the carryover test.

When doing Reproducibility, Carryover or Calibration, do not leave the screen until you finish analyzing the required number of samples.  Leaving the screen without finishing the required analysis will delete your data, which means that you must restart the test.

  1. Be sure that you completed Reproducibility check.
  2. Touch the Carryover icon.
  3. Cycle the well-mixed whole blood sample twice.
  4. Run a blank sample (air) by pressing the aspirate switch.
  5. Repeat step 4 twice, for a total of three blank samples.
  6. Touch the Summary icon to view the summary screen.
  7. Touch the Print Summary icon to print a summary report for your records. Carryover results are filed in the Hematology QC binder.
  8. If Carryover fails, contact your local Beckman Coulter Representative.

 S‑CAL Calibration Procedure 

Calibration standardizes the instrument by determining its deviation from calibration references and adjusting calibration factors as needed.  The S-CAL calibration kit helps you determine whether the calibration factors of the instrument need to be changed.  Assigned values are provided in the S-CAL calibration kit package insert.

When doing Reproducibility, Carryover or Calibration, do not leave the screen until you finish analyzing the required number of samples.  Leaving the screen without finishing the required analysis will delete your data, which means that you must restart the test.

  1. Complete the Precalibration Checks, Reproducibility and Carryover before beginning calibration.
  2. Verify that one vial of S-CAL is at room temperature.
  3. At the Main screen, touch the Setup icon.  At the Setup screen, touch the Setup Report icon.  After the calibration setup report prints, touch the Exit icon.
  4. At the Main screen, touch the QA icon.  At the QA screen, touch the Calibration icon.  The calibration assay screen appears.
  5. Refer to the TABLE OF ASSIGNED VALUES on the S-CAL calibrator package insert.
  6. On the screen, touch the field where you want to enter values, and enter the values from the TABLE OF ASSIGNED VALUES using the keypad.                 
  7. Save the values you entered by touching the Continue icon. The run screen appears.          
  8. Mix the S-CAL calibrator according to the package insert.
  9. Pipette the S-CAL calibrator into the empty mixing tube according to the instructions in the package insert.
  10. Place the well-mixed sample in the tube holder at the Cap Pierce Station and close the door.
  11. When the tube holder opens:
  1. Remove the calibrator vial from the holder.
  2. Mix the vial gently between each cycle.
  3. After analysis is complete, the results of sample #1 appear.
  1. Repeat steps 10 and 11 for each of the 11 calibration samples.  The instrument does not use results for the first replicate.  It performs statistics on replicates 2 through 11 for a total of 10.
  2. Print the results:
    • If Autoprint is on, the results print automatically.
    • If Autoprint is off, touch the Print icon.
  3. After 11 acceptable sample results, the Print Summary icon appears; touch the icon to view the summary screen.
    • If Autoprint is on, and you are using a graphic printer, a summary report prints automatically.
    • If Autoprint is off, you can print a report summary by pressing the Print Summary icon.
  4. Review the status of each result.  If PASSED appears for all the parameters, calibration adjustments are not required. Touch the Return icon.  Note:  Touching the Return icon does not update the calibration factors.  If NEEDED appears for any of the parameters, calibration adjustments are required.  Press the Save and Exit icon to automatically replace the NEEDED calibration factor with the new calibration factor. This automatically updates the instrument’s calibration parameters.

Note:  You cannot save FAILED calibration results.  Call your local Beckman Coulter Representative for assistance.

  1. Print the new calibration factors and place them behind the calibration tab in the hematology QC binder.

 Verifying That Calibration Is Acceptable

  1. Analyze QC material. The control results should fall within expected ranges.
  2. If the control results are not within the expected ranges, run it once more.
  3. If the results of the second sample are still not within the expected ranges, call your local Beckman Coulter Representative.

      Do not report patient test results until control values are acceptable.

  1. Document steps taken to bring controls within the proper range.

 

Key Points: 
References

Coulter AcT Diff2 Operators Guide  Copyright Beckman Coulter 1999,2003