Scope of service
Any test performed in the laboratory is subject to a variety of factors that may influence the outcome of the result. Some of these factors include the sample itself, the test method, reagents used and different operators carrying out the same process. Variations can also be caused by procedures that involve the measurement of analytes and reagents whereby environmental factors such as temperature and humidity may affect results. Any equipment used in the process will further introduce the opportunity for variation.
In order to provide a measure of confidence in results produced by a laboratory it is necessary to identify all factors which may contribute to variation in a process and assess their potential to influence uncertainty. Once identified these factors must be reduced or controlled to an acceptable level and a value for the range of acceptable uncertainty assigned where possible.
The CMHS has chosen, where possible, to utilise internal Quality Control material and data to establish Uncertainty of Measurement in between run data. If possible a clinical sample has been used for within run data.
For the purposes of uncertainty calculations all data is assumed to describe a normal distribution. We can therefore calculate a 95% confidence interval for these distributions and obtain the standard error (uncertainty) for any given laboratory test.
Upon request the laboratory shall make its estimates of measurement of uncertainty available to laboratory users.
Specimen acceptance policy
All specimens for Haematology and Blood Transfusion testing must conform with the instructions of the DLM Sample Acceptance Policy.
The Hospital Blood Transfusion service cannot accept incorrectly labelled samples and request forms, and operates a ‘zero tolerance policy’. Blood Transfusion specimen and request labelling guidelines are also included in the Trust Blood Transfusion Policy, available on the intranet.
Factors affecting the results or processing of Haematology tests
Here are some of the factors which could affect the results or processing of tests carried out in the Haematology department. This is not an exhaustive list. There may be other factors affecting the reporting of results which are not listed. This list applies to all sections of haematology. See individual sections for specific factors.
|Factor affecting result/processing||Outcome|
|Failed Specimen Acceptance Policy (routine samples and blood transfusion samples)||Would not process|
|Unlabelled||Would not process|
|Poorly printed label||Would not process|
|Label not straight on sample||Would not process|
|Wrong sample for requested test||Would not process|
|Wrongly labelled||Would not process|
|Sample leaked in transit||Would not process (if multiple samples were put in the specimen bag all samples would not be processed)|
|Sample broke in transit||Would not process (if multiple samples were put in the specimen bag all samples would not be processed)|
(Last reviewed November 2019)