Quality in Haematology Flashcards
Define accreditation
It is the formal third party recognition of the competence of an organisation to
carry out specific tasks
It is a recognised mechanism for assuring the quality & competence of the
services & products provided by an organisation worldwide
Write about medical laboratory inspection
Most inspected healthcare professionals within the healthcare system
Irish national accreditation body (INAB) inspect annually
Certificate is valid for 5 year cycles
Write about ISO15189
The overall Goal of ISO 15189: Medical laboratories—particular requirements for quality and competence, is patient safety
The standard requires medical labs to implement a quality management system (QMS)
And to create standardised processes that ensure staff understand and
always follow correct procedures to produce consistent results each time a process is undertaken
QMS is a collection of business processes focused on achieving your quality policy and quality objectives — i.e. what your customer wants and needs
What is quality assurance
An overall management plan to guarantee the integrity of data
What is quality control
A series of analytical measurement used to assess the quality of the analytical data
What are some pre analytical variable
- Collected from right patient and labelled appropriately, mixed
appropriately - Not from a drip site, delivered to lab promptly
- No contamination from incorrect anticoagulant
- Storage above room temperature causes fragmentation of red cells –
false high platelet count - Coagulation factors V and VIII are labile (4hr max)
- Haemolysed samples (Incorrect Hb, Will activate coagulation factors)
- Clotted sample/Partially Clotted/Activated sample
Write about validation of methods
- Method must correlate to reference method
- The method must be suitable for the intended
use - Measure its performance characteristics
– Accuracy
– Precision
– Linearity
– Limit of detection
– Interfering substances
– Reference range
– Uncertainty of measurement
Define precision
How well a series of measurements
agree with each other: It is the
closeness of agreement between
independent test results obtained
under stipulated conditions
Define accuracy
How well a measurement agrees with
an accepted value: it is the closeness
of the agreement between the result
of a measurement and a true value
of the measurement
Write about haematology controls
Haematology controls tend to be fixed cells with 3 month storage at 4°C
Stable for a few hours at room temp.
Mix correctly before use
May need to be analysed through a special QC channel on instrument
Fixed cells may not perform the same as fresh cells in the automated cell analyser – beware using for calibration
Some labs also use a ‘Drift Control’ which is made locally or bought commercially without pre-assigned values
Lab assigns values by analysing the QC material 10 times and calculating
mean and SD
What are some FBC abnormalities
Cold agglutinins -> red cells clump at RT, high MCH
Lipaemia/Icteric sample -> falsely high Hb measured
Falsely low platelet count -> platelet agglutination, giant platelets
What are some FBC confirmatory test
Delta Checking: previous results
Manual white cell count using Haemocytometer
Spectrophotometric measurement of Hb using reference standard
Platelet count on flow cytometer using CD61/CD59
Blood film examination
Write about coagulation confirmatory tests
- Check pre-analytical variables NB clots
- Always repeat
- Sampling problems
- Bubbles in sample cup
- Clot in sample probe
- Sampling too close to interface
- Repeat with extended clot observation time
- Check clinical details eg. OAT / Heparin
Write about External Quality Assessment
- All reportable tests on the scope must be attached to an EQA Scheme/Inter-
Laboratory Comparison Programme - Specimens must be treated in the same way as patient samples
- Must have a documented procedure in place in the event of an EQA failure to
implement Corrective Action (CA) - Provides a comparison of results obtained on the same sample among different
Laboratories (peer group) - EQA Schemes: NEQAS (UK), IEQAS (Labquality- Finland), Qualiris (Stago-
Coagulation), ECAT (External quality Control of diagnostic Assays & Tests) with a
focus on Thrombosis & Haemostasis, Netherlands - Distributions/Surveys per year e.g. FBC: 12 per annum
Write about EQA report and evaluation of laboratory performance
The methods by which each scheme evaluates performance is variable
Individual results are assessed against a target value
Mean, SD & CV are calculated
Gaussian Distribution plot
Deviation Index/z-score is also calculated
Grading systems A-E in Coagulation
What is the deviation Index
Less than 1 is good
Between 1 and 2 is satisfactory
Between 2 and 3 is borderline
Greater than 3 may indicate a problem
What is the action checklist for a high DI value
Exclude pre-analytical blunders
Exclude specimen quality concerns
Check analyte concentrations and its significance
Bias is evident on both specimens - possible systematic error
Large changes/variation in DI and change in bias-possible random error
Check the clinical significance of the variation - exclude a critical error
Continue to monitor -> 1 in 20 results will be outside +- 2 SD
What should you do if bias is evident on both specimens and indicates a possible systematic error
Check IQC
Check trends in analytical performance score
Check trends in patient’s results
What should you do if there is a large change/variation in DI and change in bias due to possible random error
Check IQC
Check maintenance, reagent or other changes
Check operator training
What is a critical error and give three examples
One which has the potential to change a patient’s pathway, regardless of the effect on the ultimate diagnosis arrived at which denies that person the earlies opportunity of correct treatment
WBC counting for clozapine patients
Incorrect mutational analysis in molecular diagnostics
Incorrect Hb A2 result in antenatal screening
What action is taken by EQA if a lab is out of control
A standard letter is sent to participants alerting them to the error
Offer of assistance from the Scheme Director
In the UK, persistent poor performance Laboratories are reported to the NQAAP (National Quality Assurance Advisory
Panel) who report to: Joint Working Group on Quality Assurance.
What four actions should be taken by a laboratory out of control
Discuss the unsatisfactory performance/outwith consensus with the Consultant
Perform Root Cause Analysis to find possible reasons for the failure
Raise a non-conformance on Q-Pulse with the Quality Officer/Manager
Request a repeat sample from the Scheme (where possible)
What are four non-analytical reasons for EQA failure
Assaying wrong samples
Assaying the right sample in the wrong order
Incorrect transcribing results
Use of incorrect units
Technical errors: incorrect reconstitution, faulty pipetting, double addition
What are five analytical errors that could cause EQA failure
IQC errors
Analyser errors
Contaminated water used for reconstitution of lyophilised samples
Inadequately trained staff
Inexperienced laboratory staff
What four pieces of corrective action can be done
- Constant documented contact with the EQA provider
- Identify the Root Cause
- Fix the problem
- Repeat the test and submit again
When would a lab undergo suspension of accreditation
- Two consecutive failures, INAB must be informed
- Resulting in accreditation of the test being suspended
- Inform users
