WESTGARD RULE and L- J curve., Slides of Medical Biochemistry

Download WESTGARD RULE and L- J curve. and more Slides Medical Biochemistry in PDF only on Docsity!

Westgard

Rules

Dr Bharat Kumar Pareek

st

year Resident

Dept. of Biochemistry

S.M.S. Medical College

• (^) Westgard rule AKA Multirule Quality Control was developed by Dr. James Westgard based on statistical concepts. DR JAMES WESTGARD FOUNDER

 Westgard rule/Multirule Quality Control(QC)

• (^) The formulation of Westgard rules were based on statistical methods. Westgard rules are commonly used to analyze data in LEVEY–JENNINGS (LJ) chart.
• The advantages of multirule QC procedures are that false rejection can be kept low while at the same time maintaining high error detection.
• Westgard rules are used to detect both random and systematic errors.

 How to perform Multirule QC?  Choose a good quality control material.  (^) Run control at least 20 times (different runs) – once or twice daily  (^) Collect your control measurements  (^) Obtain the mean and Standard deviation for 20 points of data  (^) Use the data and draw Levey-Jennings(LJ) chart

 Levey-Jennings (LJ) Chart

• (^) It is a graphical method for displaying control results and helps in evaluating whether a procedure in-control or out-control by applying westgard rules.
• (^) Daily control values are plotted versus time.
• (^) Lines are drawn from point to point, to understand any systematic or random errors.
• (^) Every control that we run is plotted on LJ chart. LJ chart has x and y axis. On x axis there will be no of days/time while on y axis there will be value of mean and standard deviation.

 Levey-Jennings (LJ) Chart

Types of Westgard rules  Most common rules-

1. 1 2s Rule
2. 1 3s Rule
3. 2 2s Rule
4. 4 1s Rule
5. R4s Rule
6. 8 x Rule
7. 10 x Rule
8. 12 x Rule

Other rules-

1. 2of32s Rule
2. 3 1s Rule
3. 6 x Rule
4. 9 x Rule
5. 7 T Rule 1 = how many time rule is violated 2S = which standard deviation is violated

There are 6 Basic Rules

 1 3s Rule:- 1 3s control rule is commonly used with a Levey-Jennings chart. It refers when the control limits are set as the mean plus 3s and the mean minus 3s. A run is rejected when a single control measurement exceeds the mean plus 3s or the mean minus 3s control limit.

 2 2s Rule:- 2 2s refers when 2 consecutive control measurements exceed the same mean plus 2s or the same mean minus 2s control limit. It requires corrective action and run is rejected

 R4S Rule:- R 4s

• refers when 1 control measurement in a group exceeds the mean minus 2s and another exceeds the mean plus 2s.This rule should only be interpreted within run ,not between run. Test run must be rejected.

 8 x Rule:- 8x – refers when 8 consecutive control measurement fall on the one side of mean. Test run must be rejected.

 12 x Rule:- 12x – refers when 12 consecutive control measurements fall on one side of the mean. Test run must be rejected.

• (^) This decision tree helps to decide whether to reject or accept a run. If your answer is YES, it means that rule is violated.