|Year : 2020 | Volume
| Issue : 2 | Page : 92-95
Study of pre-analytical errors in haematology laboratory: A single-centre experience
Harish Chandra, Arvind Kumar Gupta, Neha Singh
Department of Pathology and Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
|Date of Submission||14-May-2020|
|Date of Decision||23-Jul-2020|
|Date of Acceptance||11-Sep-2020|
|Date of Web Publication||15-Dec-2020|
Dr. Harish Chandra
Department of Pathology and Laboratory Medicine, All India Institute of Medical Sciences, Rishikesh - 249 201, Uttarakhand
Source of Support: None, Conflict of Interest: None
Aims and Objectives: Total quality management is an essential component of laboratory to maintain quality and includes pre-analytical, analytical and post-analytical phases. Pre-analytical phase starts from ordering investigation by the clinician till it is analysed in the laboratory. It is essential that a pathologist is aware of the confounding factors that may lead to pre-analytical errors with the knowledge of reducing them to improve the quality of the lab. The present study was conducted to evaluate the pre-analytical errors in the haematology laboratory and steps taken to minimise it. Materials and Methods: The study was conducted in the Haematology Laboratory of Pathology Department, All India Institute of Medical Sciences, Rishikesh, over a period of 4 years and included all the blood samples analysed in the lab. The pre-analytical variables including requisition form, patient preparation, labelling, sample collection, quality and transportation were analysed for the errors along with the corrective actions taken to minimise them. Results: A total of 25,15,583 investigations were received in the haematology laboratory over a period of 4 years. The total errors observed in the haematology lab in pre-analytical phase were 13,031 comprising 0.51% of total haematological investigations during the study period. The most common error observed was due to clotted sample (40.3%), followed by haemolysed samples (15%) and incomplete or wrongly filled requisition forms (10%). Conclusion: Pre-analytical phase forms an integral part of total quality management system and its analysis is essential to minimise the errors in haematology lab. The quality of blood sample with completely filled requisition forms and prompt transportation of sample to the lab are essential components to avoid pre-analytical errors. In addition, continuous training and acknowledgement of non-conformance with root cause analysis is the basic key for reducing errors and improving quality of haematology lab.
Keywords: Haematology laboratory, pre-analytical errors, root cause analysis
|How to cite this article:|
Chandra H, Gupta AK, Singh N. Study of pre-analytical errors in haematology laboratory: A single-centre experience. J Med Evid 2020;1:92-5
|How to cite this URL:|
Chandra H, Gupta AK, Singh N. Study of pre-analytical errors in haematology laboratory: A single-centre experience. J Med Evid [serial online] 2020 [cited 2022 Aug 12];1:92-5. Available from: http://www.journaljme.org/text.asp?2020/1/2/92/303573
| Introduction|| |
Total quality management is an essential component of any laboratory to maintain its quality, reliability and reduction of errors. The laboratories try to maintain good quality control, which implies that requirements of quality are verified by operational techniques while quality assurance provides confidence that the process fulfils quality requirements. Pre-analytical, analytical and post-analytical phases are the three components of total quality management. Pre-analytical phase in haematology laboratory starts from the ordering of the investigation by the clinician till it is analysed and reported by the pathologist. It includes multiple steps from filling of the requisition form, sample collection, transportation, processing and smear preparation in the laboratory. Although efficiency of the analytical phase is considered to be the main focus of quality indicators, pre- and post-analytical phases are found to be more associated with errors., It has been observed that pre-analytical errors range from 60% to 80%, while analytical errors constitute only 7%–13% of estimated proportion of laboratory errors., The impact of these errors may not only be related to delay in diagnosis and treatment with inconvenience to the patient but at times may also endanger patient's life and safety. Thus, it is essential that pathologist is aware of the confounding factors that may lead to these errors with the knowledge of reducing them to improve the quality of the lab.
The present study was therefore conducted to evaluate the various pre-analytical errors that were encountered in the haematology laboratory and the steps taken to minimise it.
| Materials and Methods|| |
The study was conducted in the Haematology Laboratory of Pathology Department, All India Institute of Medical Sciences, Rishikesh, situated in North Sub-Himalayan region of India. The study was conducted over a period of 4 years from 1st March 2016 till 29th February 2020 and included all the blood samples which were analysed in the lab both from the outpatient and inpatient departments. The blood samples were collected in ethylenediaminetetraacetic acid anticoagulant vacutainers for plasma and clot activator gel vacutainers for serum. The samples were processed within 4 h of collection but not at fixed time. The samples were run on automated cell counter Beckman Coulter LH-750 (California, USA) and Sysmex XN-1000 (Japan) for complete blood count analysis. The pre-analytical variables were analysed for test ordering with requisition form, patient preparation, labelling, sample collection, quality, transportation and sample sorting. The corrective actions taken to prevent these pre-analytical errors were also studied.
| Results|| |
A total of 279,510 samples were received in the haematology laboratory with total 2,515,583 haematological investigations done over the period of 4 years. The total errors observed in the haematology lab in pre-analytical phase were 13,031 comprising 0.51% of total haematological investigations and 4.6% of the total samples received during the study period. [Table 1] shows the different types of pre-analytical errors observed in the study. It shows that the most common error observed was due to clotted sample followed by haemolysed samples and incomplete or wrongly filled requisition forms. [Table 2] shows the pre-analytical errors with corrective actions taken to minimise them.
| Discussion|| |
Recently, it has been reported that error rate encountered in the laboratory medicine is less than in other areas of medicine. Although the major concern of most of the laboratories lies for the analytical phase of reporting, it comprises least errors in the total testing process. The pre-analytical phase bears the major burden of errors in laboratory medicine, followed by post-analytical phase. Carraro and Plebani observed that 62% of errors were due to pre-analytical phase events, while 23% after testing is complete in post-analytical phase and interestingly these figures were similar to those observed 10 years ago. The pre-analytical errors are said to be more associated with human mistakes which are preventable., It was observed in the present study that the pre-analytical errors constituted 0.5% of the total haematological investigations, while it was 4.6% of the total samples received. This is an important observation as other studies from Indian subcontinent have reported lesser pre-analytical errors ranging from 0.38% to 1% of the total samples received.,, However, these studies have included only limited haematological parameters for pre-analytical analysis which may be responsible for lesser errors. These findings also emphasise the need of training of phlebotomists, nursing staff and health-care workers from other departments by experts from laboratory to minimise errors involved in sample procurement and transfer.
It was also observed in the present study that the most important cause of pre-analytical error was poor sample quality and it constituted 62.7% of total errors. [Table 1] shows that poor sample quality was either due to clotted samples, haemolysed samples, lipaemic sample or due to poor technical quality of peripheral smears. It was observed that clotted samples constituted the majority of errors (40.3%) in this study. Clotted samples have always remained a major problem in the haematology lab and may constitute 43%–51% of sample rejections in haematology lab., Previous studies from Indian subcontinent have also reported clotted samples as the major cause of pre-analytical error in haematology lab., The most important reason for clotted samples is usually due to poor practice during phlebotomy or improper mixing sample after blood withdraw. The incorrect ratio of blood and anticoagulant may also be another reason for clotted samples, but this was not a reason in our study as we are using commercial vacutainers with fixed appropriate quantity of anticoagulants. The authors further suggest that proper knowledge and training of phlebotomist may prove beneficial in this regard.
Another important variable which is responsible for errors in pre-analytical phase is haemolysed samples. The main reason behind this factor is vigorous mixing of samples after withdrawn of blood and the corrective action which may be taken is training and advisory to the phlebotomist to avoid such mixing. It was also observed in the present study that the diluted samples was responsible for pre-analytical errors in 3.4% of cases and the practice of blood withdraw from the infusion site was the principle reason behind it. It has been suggested in the literature that the blood should never be withdrawn from the same arm where intravenous tube is present to avoid diluting of samples and thus leading to erroneous results.,
The poor quality of stained smears was observed to be another factor responsible for pre-analytical errors?. It was observed that lack of knowledge of proper staining or variation in atmospheric temperature and pressure may hamper proper staining leading to poor quality of smears. Therefore, the authors suggest that proper training to technician accompanied by maintenance of system operating procedure for staining by every laboratory depending on atmospheric conditions of that area is necessary to minimise this error.
Another important error that was observed in our study was incomplete or wrongly filled requisition forms which constituted 10% of total pre-analytical errors. Lack of complete information on investigation requisition forms has always been a problem for smooth reporting by pathologist. This error of incomplete requisition form has been observed in all the branches of pathology including cytopathology and histopathology. The authors suggest that extraction of information telephonically from clinician or patient and bar coding may be used to minimise this error. In addition, providing training and advisory services to the health professionals highlighting the importance of complete correct clinical information for proper reporting of any investigation may also be useful in this regard. The computerised order entry with check boxes for clinical information may also be helpful.
The present study also observed that delay in transportation of sample from the wards to lab was observed in 4.2% of cases and this error can be avoided by quick transportation of samples without delay. It has been suggested that pneumatic system may prove beneficial to avoid this delay and further preventing the incorrect haematological reports.
However, an important limitation of the present study is that some cases may have been missed due to lack of traceability and recording, and therefore, the authors suggest an extended study with vigilant recording should be done to give more detailed account of pre-analytical errors in haematology laboratory.
| Conclusion|| |
Pre-analytical phase forms an integral part of total quality management system and its analysis is essential to minimise the errors in haematology lab. The quality of blood sample with completely filled requisition forms and prompt transportation of sample to the lab are essential components to avoid pre-analytical errors. In addition, continuous training and acknowledgement of non-conformance with root cause analysis is the basic key for reducing errors and improving the quality of any haematology laboratory.
The authors acknowledge the haematology technician Mr Anurag Pant at the Department of Pathology and Lab Medicine, All India Institute of Medical Sciences, Rishikesh , India, for his constant support.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]