INTRODUCTION
To comply with UKAS Medical Laboratories it is necessary to determine the uncertainty of results where relevant. Full consideration and awareness of all identifiable components that contribute to the uncertainty of a test will allow valid results to be obtained and may also indicate aspects of a test or procedure which need improvement.
Uncertainty of measurement is normally associated with a quantitative result. Although most results in Cellular Pathology are not quantitative, determining the possible errors during the processing of samples provides information on total error and creates the doubt (uncertainty) of the true validity of the result.
Cellular Pathology uses the evidence from the repeatability or reproducibility of a test where possible to meet this standard.
Please note that a negative cytology report does not exclude the presence of disease.
SOURCES OF UNCERTAINTY OF MEASUREMENT
There are two types of uncertainty as defined by the International Organization for Standardization.
Type A is the statistical figures for specific assays and includes:
Type B is the non-statistical measures and can be grouped as:
FACTORS AFFECTING THE UNCERTAINTY OF MEASUREMENT
The following factors can all affect the quality of results in Cellular Pathology:
In order to minimize the uncertainty of measurement, all of these factors must be evaluated, monitored and where possible actions taken to minimize them.
MONITORING AND MINIMIZING UNCERTAINTY OF MEASUREMENT IN COMPLIANCE WITH ISO 15189
PRE-EXAMINATION | |||
LAB ACTIVITY TO MONITOR | LAB ACTIVITY TO MINIMIZE | ||
PATIENT STATE & PREPARATION | Ensure all relevant clinical information is supplied on EPIC and on request forms from external sources | Advice available from http://www.exeterlaboratory.com/ and the laboratory at 01392 402991 |
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SAMPLE COLLECTION TIME | Lab to note any samples not received promptly in lab | As Above | |
SPECIMEN COLLECTION AND HANDLING | Lab to log all sample and/or request form errors (Includes labelling, leakage and missing samples) |
As Above
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SAMPLE TRANSPORT | Delays due to transport logged | Transport policy on Intranet | |
THIRD PARTY | Ensure third party compliant with any registration or accreditation requirements | Annual review of referrals to third parties | |
SAMPLE & BODY STORAGE | Fridge temperature monitoring | Procedure in place for logging any incidents or equipment downtime |
EXAMINATION | |||
LAB ACTIVITY TO MONITOR | LAB ACTIVITY TO MINIMIZE | ||
CALIBRATION | Timely calibration of appropriate equipment | Ensure companies performing calibration comply with UKAS standards | |
INSTRUMENT PERFORMANCE | Error logging of equipment downtime | Preventative Maintenance and Servicing | |
REAGENTS | IQC & EQA monitored. Logged with lot numbers and expiry dates | Use of CE or UKCA marked reagents. All new methods verified prior to use | |
INTERNAL QUALITY CONTROL |
All IQC checks documented in SOPs Stain quality Slide quality
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Ensure all staff trained and competent for IQC Stain and slide checking for early recognition of any issues |
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EXTERNAL QUALITY ASSURANCE | Ensure laboratory enrolled in EQA or ILC schemes and relevant staff take part | Monitor EQA and ILC outcomes | |
STAFF COMPETENCY | Incidents and training issues logged and addressed |
Training and competency updates for all staff Ensure staff comply with CPD requirements Retain training approval with IBMS
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CONSUMABLES | Inspect and document consumables upon arrival to laboratory. | Avoid damaged consumables being used. |
POST – EXAMINATION | |||
LAB ACTIVITY TO MONITOR |
LAB ACTIVITY TO MINIMIZE
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REPORT |
Avoid transcription errors prior to release of results Ensure correct patient management
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Reports checked by qualified staff | |
INTERPRETATION | Ensure meaning of report is unambiguous | All reports checked by reporting Pathologist or AP | |
STORAGE, RETENTION AND DISPOSAL OF CLINICAL SAMPLES | Ensure compliance with current RCPath and HTA guidance | SOP in place for retention and disposal of clinical samples; audit procedures |
Specimen Labelling Procedure