Quality

Question 1

What is QC? Internal vs External

Answer 1

Set of procedures and measures implemented in a pathology laboratory to ensure the accuracy, reliability, and consistency of laboratory test results.
It involves the regular use of control materials, monitoring systems, and performance checks to detect, reduce, and correct errors in the analytical process.

Internal QC
- Performed daily or per batch using known control samples.
- Involves running commercially prepared control samples with known values.
- Ensures that analyzers are performing correctly

Review of QC:
- Daily QC logs and Levey-Jennings charts are used to monitor trends and identify shifts or random errors.
- Immediate corrective action is taken if QC results fall outside acceptable ranges.

External QC
- Periodic participation in national EQA programs
- Compares the lab’s results with those from other labs or a central body.
- Assesses overall performance and identifies potential systematic errors.

External Quality Assurance:
- a program in which multiple specimens are periodically sent to laboratories for analysis and/or identification, in which each laboratory’s results are compared with those of other laboratories in the group and/or with an assigned value, and reported to the participating laboratory and others.

Such a program may also compare an individual’s results with those of their peer group.

Question 2

SOP - Standard Operating Procedures

Answer 2

Clear instructions for sample handling, analyzer operation, and result validation.

Ensures consistent practices across personnel and shifts.

Question 3

Levey-Jennings charts

Answer 3

Used in to monitor internal quality control (IQC) results over time.
Provided a visual representation of how a control result compares to the expected value and help in detecting:
- Systematic errors (trends or shifts)
- Random errors (scattered or erratic results)
- Analyzer drift over time

Charts are essential for early detection of problems with hematology analyzers (e.g., for complete blood count, WBC differential, platelet counts) before patient results are released.

Question 4

Steps taken to minimize analytical issues

Answer 4

1. QC
   -Quality control is the process of ensuring that analyser results are accurate, and that any issues are identified so that they can be corrected
   -In our laboratory, QC involves running control samples on a regular basis
   -Control samples usually consist of a normal and abnormal control - these are typically provided by the manufacturer and provide a result of a known value, with an acceptable range (which is typically +/-2 standard deviations)
   –Westgarth rules are followed so that if results are outside the acceptable range, appropriate action is taken that may include
   —Withdrawing results up to the last QC in range, rerunning specimens, replacing reagents, replacing the QC, maintenance

-Furthermore, one some analysers ‘drift’ can be monitored
–Stable parameters (such as MCHC, MCH, MCV on our FBE analyser) are batch monitored (in batches of 20)
–If these values ‘drift’ outside of what is considered normal, it may prompt further investigation (however patient population being tested should be taken into account)

2. QA
   -QA is the process of ensuring the entire laboratory process, from bedside collection to reporting of results, is being performed appropriately and in line with regulatory standards
   -Depending on the test in question, a governing body (e.g. the RCPA) will provided the laboratory with samples on a regular basis of a known value, to ensure that each laboratories analysers and process are providing results consistent with a national standard, as well as comparable to labs using the same analyser/same method of analysis
   -QA failures prompt further investigation

-Furthmore, our laboratory is involved in a sample exchange for some of our tests/analysers
–e.g. Once a week, a coagulation sample exchange occurs where frozen plasma is sent to each of our labs on a Thursday to ensure concordant results

3. Maintenance
   -Regular maintenance of analysers is essential to ensuring analytical errors do not occur
   -Will ensure analysers continue to run smoothly
4. Escalation
5. NATA inspections/accreditation
   -Our laboratory is held to NATA standards
   -Regular NATA inspections ensure that the laboratory and its analysers are held to a standard
   -Failure to meet standards may result in a loss of accreditation, and make results produced invalid
   -This helps to ensure analytical errors are minimised
6. Calibration
   -Analyser calibration with manufacturer provided samples is essential to minimizing analytical issues
   -Calibration should occur with: every major maintenance episode, change in reagent batch number, significant QC/QA issues, on a regular pre-determined basis (e.g. monthly)