Internal and External Quality Control Assignment


Accredited pathology laboratories operate within a regulatory framework that demands implementation, participation in and monitoring of IQC and EQA processes. Explain

  1. a)  the importance of each of IQC and EQA to producing quality patient results,
  2. b)  briefly, the roles NPAAC and NATA play in this regulatory framework and
  3. c)  what ISO15189 and the NPAAC guidelines mandate pertaining to IQC and EQA including 
reference to the specific pertinent sections

Include a final one to two sentences on the overall rationale for this project in terms of your professional development as a medical laboratory scientist.


Describe how each of the IQC and EQA parts of the QC project were organised, including what was analysed and the method used, the processes of recording/documentation and analysis of results and the role of the individual student and the class in this model (1 page max). Do not reiterate the detailed content of the method or report sheets.

NOTE: The same assay is performed for both IQC and EQA analyses.

  • To 5 labelled tubes (Eppendorf, 2 mL) add 900 μL Bromocresol Green (BCG) reagent (labelled as ‘Albumin BCG reagent’) and pre-Incubate the tubes at 37oC in the heat block for 10 minutes.
In Weeks 7 and 10 only, prepare two extra tubes containing 900 μL BCG Reagent.
  • To the 5 tubes, add 9.0 μL of one of the following (follow table below)
  • Distilled water
  • Standard (also called calibrator, with a known, accurate concentration of albumin)
  • IQC Normal serum sample (which has a known “Target Value” albumin concentration)
  • IQC Abnormal serum sample (which has a known “Target Value” albumin concentration)
  • Patient serum sample (with an unknown concentration of albumin)
In Weeks 7 and 10, to tubes 6 & 7 add 9.0 μL of one the following (follow table):
  • EQA Albumin Sample (A) (with an unknown Target value)
  • EQA AlbuminSample (B) (with an unknown Target value) 
Table 1. QC Experiment – Serum Albumin Assay – BCG method; Contents of Tubes
  • Mix each tube immediately after addition using a vortex and incubate each tube for exactly 90 seconds at 37oC. The reagent blank does not need a timed incubation (no reaction will occur).
  • Read the absorbance of tubes 2-5 (2-7 in weeks 7 and 10) at 630 nm vs the Reagent Blank (ie. Set Ref or zero absorbance with Tube 1) immediately after the 90s incubation period and record on report sheet.
  • Calculate the two IQC and Patient concentration results using Beers’ Law as set out on page 14 and enter calculations and results onto IQC report sheet.
  • In Weeks 7 & 10 also calculate the two EQA sample concentration results using Beers’ Law and enter results onto the EQA report Sheet and the Google Forms data portal.
  • Calculate the z-scores for the two IQC samples, record the calculations and results on the report sheet and determine the validity (acceptability) of the patient result as specified on the report sheet.
  • Complete the report sheet(s) and submit electronically for review and supervisor’s signature.


Internal Quality Control (IQC)

You will measure the concentration of serum albumin in three samples – a Patient sample, and two QC Samples with known target values for albumin. You will trial the assay and recording of data in week 2 (training) and then repeat the analysis for 7 weeks (weeks 3-8 & 10) using the same IQC samples but a different patient sample each week; these seven will form part of your project final report. The IQC samples will be ‘normal’ and ‘abnormal’, that is one will have a concentration of albumin that falls within the reference range and one will have a concentration that falls outside the reference range for albumin.
You will be acting as a specific Laboratory (your ‘OWN’ Lab) and your weekly IQC results will be taken to represent your laboratory in its own “Internal Quality Control” (IQC) program. If the IQC Samples’ results are within certain (“acceptable”) limits of the “Target” QC Values, then you will accept that the assay run is “in control” and the result for the Patient Sample is correct/valid and can be released to the requesting clinician.

External Quality Assurance (EQA)

In addition to attaining your IQC results, twice during the semester (weeks 7 and 10) two additional serum ‘EQA’ samples will be analysed. The concentration of these extra samples will be unknown at the time of the assay. The results for your EQA samples will be recorded and the results of all students (acting as ‘labs’) will be collated as part of an EQA program modelled on ‘real world’ practice. As each result represents that of a specific lab, the collated results are those of up to 80 laboratories using the same Bromocresol green (BCG) method to analyse the same EQA serum albumin samples. For each of the two week’s EQA analyses, students will be provided with the collated list of lab results and a YOUDEN PLOT graphical representation of the data. Each student will then analyse the group results to assess

  1. The performance of your OWN LAB compared to the peer group and
  2. The overall performance of the BCG method used for analysing serum albumin.


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