What is a trend on a Levey-Jennings chart?

What is a trend on a Levey-Jennings chart?

Trends can be caused by deterioration of reagents, tubing, or light sources. Shifts and trends can occur without loss of precision and can occur together or independently. The occurrence of shifts and trends on the Levey-Jennings control chart is the result of either proportional or constant error.

How do you interpret the results of a quality control chart?

The following rules can be used to properly interpret control charts:

1. Rule 1 – One point beyond the 3 σ control limit.
2. Rule 2 – Eight or more points on one side of the centerline without crossing.
3. Rule 3 – Four out of five points in zone B or beyond.
4. Rule 4 – Six points or more in a row steadily increasing or decreasing.

What is trend and shift?

Applicable to run charts and control charts, a shift in its most basic form is seven points in a row either above or below the centerline. A trend is seven points in a row in an upward direction or seven points in a row in a downward direction.

What is internal quality control?

Internal quality control (IQC) is a process for checking that the uncertainty at validation does not deteriorate after validation, that is, when the method is in routine use.

What is the importance of Levey Jennings chart in quality control?

A Levey–Jennings chart is a graph that quality control data is plotted on to give a visual indication whether a laboratory test is working well. The distance from the mean is measured in standard deviations.

What are the Westgard rules and how should they be used to assess quality control results?

What are Westgard Rules? Westgard Rules are multirule QC rules to help analyze whether or not an analytical run is in-control or out-of-control. It uses a combination of decision criteria, usually 5 different control rules to judge the acceptability of an analytical run.

When interpreting control charts what does the statement out of control mean?

When points on a control chart move outside the upper or lower control limit, the process is said to be “out of control.” As long as the points are within control limits, the process is “in control.” But, what does an out of control process indicate? Many believe that an out of control process produces defective parts.

What does UCL and LCL mean in statistics?

UCL = Upper Control Limit. LCL = Lower Control Limit. Control Limits are calculated based on the amount of variation in the process you are measuring. One measure of variation is standard deviation*. A common method of calculating control limits is the mean +/- three standard deviations.

What is quality control in clinical biochemistry?

Quality control is one of the components of quality assurance program. In Clinical Biochemistry it refers to maintenance of quality of the laboratory tests during analysis. Two types of quality control are practiced in clinical biochemistry: Internal and external quality controls.