QC Rejection Rules (Westagard Rules) in Simplified Table

Internal quality control results are monitored by using Levy Jennings Chart (LJ Chart / Control chart) with applicable westgard rules.  Herewith i provided the five basic  westgard rules in simplified table to make decision on Accepting/Rejecting the QC run. 

Laboratory professionals can download the below  table (download link provided) and displayed as poster in respective lab sections for easy reference.

DOWNLOAD THE POSTER  

When a rule is violated :

Warning Rule = use another rules to inspect the control points

Rejection Rule = "Out of Control"

• Stop Testing
• Search for recent events that could have caused changes
• Examine environmental conditions.
• Identify and correct problem
• Repeat  testing on patient samples and controls
• Follow manufacturer’s troubleshooting guide
• Refer to instructions of manufacturers of equipment, reagents or QC / calibrator
• Do not report patient samples until problem is solved and controls indicate  proper performance

Points of QC Failures : 

• Instrument Failure:  
• Check for error messages (printed or displayed). 
• Refer to the troubleshooting section of the instrument manual. 
• Reagent, Quality Control Materials, Calibrators: 
• In correct reconstitution, i.e. wrong or contaminated diluent or use of the wrong volume of diluent. 
• In correct storage, e.g. left at room temperature for excessive amount of time. – Prepare fresh (allow enough time to dissolve) 
• NOTE: Bulk liquid reagents may be contaminated. 
• Human: 
• Reread the method 
• Check whether the correct sample volumes or reagents were used.
•  Make sure that a step in the procedure was not missed. 
• Were the correct parameters entered?

Source Reference :
https://www.westgard.com/mltirule.htm

NABL 112 -Specific Criteria for Accreditation of Medical Laboratories  ( Issue - 4, Issue date -11-Feb-2019 )
https://www.aacb.asn.au/documents/item/3078 (Troubleshooting Failed QC, by Dr Douglas Chesher)

POSTED BY: 

Mr.V.SELVAM, M.Sc (Biochemistry)

Consultant - ISO 9001 & NABL (ISO 15189 & ISO 17025)

MindEmits Consulting Services, 

Chennai, Tamilnadu, India

✆ +91-9940014466

☭  selvam.mindemits@gmail.com