Lab 2: Quality Control, Levey- Jennings, & westgard Rules Flashcards

What is Quality Control (QC)?

Manufactured samples tested like patient samples to verify instrument reliability.

Why should QC samples have the same matrix as patient samples?

To mimic actual patient testing conditions.

How are QC ranges established?

Through manufacturer ranges, laboratory validation, and peer-group data.

What is plotted on a Levey-Jennings Chart?

Values relative to the mean and standard deviations (SDs)

Why are standards deviations important on a Levey-Jennings Chart?

They show how far QC results are from the expected mean.

What are Westgard rules?

Statistical QC rules used to determine whether an analytical run is acceptable.

What is the 1_2s rule? Does it automatically reject the run?

One control exceeds +2 or -2 SD from the mean. It’s a warning rule.

• No, the rule serves as a warning and triggers review so it’s not automatically rejected.

What is 1_3s Rule? What action results from a 1_3s violation?

One control exceeds +3 or -3 SD from the mean.

• The run is rejected in this violation.

What’s 2_2s rule? What action results from this violation?

Two consecutive controls exceed the same +2 or -2 SD.

• The run is rejected.

What is the R_4s rule? Is it evaluated within- run or between-run?

+2 or -2 SD and another exceeds -2 SD in the same run.

• The evaluation is within-run only.

What is the 4_1s rule? What action results from this violation?

Four consecutive controls exceed the same +1 or -1 SD limit.

• The run is rejected

What is the 10x rule? What action results from this violation?

Ten consecutive control results fall on one side of the mean.

• The run is rejected.

What is the first step when QC fails?

When the QC fails first all failed QC levels should be rerun.

What steps should be taken when QC rerun still fails?

Steps when rerun still fails:

1. Prepare new QC material

2. Replace reagent

3. Recalibrate instrument/ reagent

4. Contact technical support

When QC fails when are patient results released?

Patients results are then only released when QC is acceptable.