Archives of Medicine

Keywords

Pre-analytical; Laboratory errors; Biochemistry laboratory; Rejections; Samples haemolysis

Introduction

Nowadays, there is an increasing attention focused on patient safety and improving the performance of clinical laboratory, since physician’s diagnostic and therapeutic decisions are mainly dependent on the accuracy and reliability of laboratory results. During sample processing and testing, errors might be generated from three phases; pre-analytical (steps outside the walls of the laboratory), analytical (specimen testing) or post-analytical phase (final phase of the laboratory process including; production of a final value, result and report). Despite the significant decrease in the rates of analytical errors, the majority of errors are found to be arising mainly from the pre-and post-analytical phases with a total of 93% [1]. In 2007, Carraro and Plebani reported 61.9% of the laboratories errors were pre-analytical, 15% were analytical, and 23.1% were post-analytical [2]. Similarly, Goswami et al. found that the pre-analytical errors were the most commonly encountered, with a frequency of 77.1% followed by postanalytical accounting for 15% and analytical contributing upto 7.9% [3]. These results are in agreement with the finding of Astion and his colleagues, which showed that 71% of the errors were observed within the pre-analytical testing phase, while the analytical and the post-analytical phases showed 18% and 11% respectively [4].

A number of other studies have also reported that the highest error rate was related with the pre-analytical phase and that these are mostly generated from mistakes in sample containers, insufficient volume of the sample, handling, storage, transportation and requesting procedures [5-7]. Another study showed that the majority of rejections were caused by sample hemolysis in the clinical biochemistry laboratory [8].

The Emergency Department (ED), requires urgent and accurate test results, however, workload pressures often lead to pre-analytical errors such as incorrect patient identity (ID) and test tubes as well as inadequate mixing, leading to clotting of patient’s specimen [2].

The types of error in the pre-analytical phase seem to be vary in different departments even at the similar clinical laboratories. Pre-analytical laboratory errors pose a serious hazard for patient’s health, lead to decreased patient satisfaction and increased healthcare costs [9,10]. Moreover, these laboratory errors often lead to misdiagnosis, delay in reporting, unnecessary sample redraws, improper diagnosis and treatment that follows [11]. In 2011, Plebani and Piva found that 25-30% of laboratory errors have an impact on patient’s care [5].

Preventing errors in the pre-analytical steps requires excellent communication, closer relationships among all members of the health care team (laboratory personal,physicians and nurses) and technological developments including; wristband, bar-codes and pre-analytical workstations. Additionally, automation and computer systems have greatly simplified many aspects of clinical laboratory tasks, significantly improving the rate and minimizing preanalytic errors, which in turn lead to improved care and well being of the patient.

The aim of this study is to investigate the main causes of pre-analytical errors that led to sample rejection at clinical biochemistry laboratory at Hera’a General Hospital in Makkah city.

Material and Methods

This study is based on a retrospective analysis of the results obtained from clinical biochemistry lab at Hera’a General Hospital at Makkah, Saudi Arabia.

At biochemistry lab, routine and reference testing are provided. Upon sample receiving, the department’s supervisor visually detected any defect in the specimen. Laboratory personnel were then asked to register rejections and its causes, in the problem notification log book if any preanalytical error. The data generated was reviewed on a weekly basis.

Samples were collected in the clinical biochemistry laboratory for the period of January 2014 to December 2014.

Errors that occurred during pre-analytical phase have been identified as incomplete patients data on request form, quantity not sufficient (QNS), clotted sample, visible haemolysis after centrifugation, mismatch, wrong tube and others. The frequency of the main factors affecting the preanalytical quality of test results was calculated. Data was analyzed statistically using SPSS version 19.

Study’s proposal was approved by the Research Ethical Committee of the Health affairs and Committee of the Hera’a General Hospital in Makkah.

Results

A total of 102197 samples were received by clinical biochemistry laboratory from the patients admitted in the wards as well as outpatient department (OPD) during the period of this study. Venous blood samples were considered unsuitable according to the following accepted criteria: incomplete patients data on request, quantity not sufficient (QNS), clotted sample, visible haemolysis after centrifugation, mismatch, wrong tube and others.

The overall rejected samples, which were found unsuitable for further processing were 2116 samples. This accounted for 2.07% of all samples collected in the biochemistry laboratory (Table 1).

Table 1; Number of total received, total rejected and percentage of rejected samples with pre-analytical errors during January to December 2014.

The most frequent pre-analytical error encountered was that of sample hemolysis with an incidence of 35% (Table 2). Clotted samples from admitted patients and OPD constituted the second most frequent reason for sample rejection during pre-analytical phase reaching to 19.5% (Table 2). Mismatch of patient’s information on test request with that on sample tube and incomplete patient’s information accounted for 5.5% and 6.6% of the total rejected samples respectively (Table 2).

Table 2: Distribution of pre-analytical errors frequencies during January to December 2014.

The highest percentage of rejected samples was reported from the Emergency Department (ED), which presented with 24% followed by Intensive Care Unit (ICU) with 14.18% (Table 3). On the other hand, rejected samples from outpatient department showed much lower percentage (1.8%) during January to December 2014 (Table 3).

Table 3 : Number of rejected samples from different wards and outpatient department (OPD) in the clinical biochemistry laboratory during January to December 2014. Emergency (ER), Intensive Care Unit (ICU), Male Medicine Ward (MMW), Female Medicine Ward (FMW), Male Surgery Ward (MSW),Female Surgery Ward (FSW), Pediatric Ward (PW), Pediatric Intensive Care Unit (PICU), Neonatal Intensive Care Unit (NICU), Obstetric Gynecology (OB) and Labor Ward (LW).

Discussion

Despite significant advances, which have transformed laboratory diagnostics from manual and labor-intensive process to an automated one, clinical laboratory still shows a number of pre-analytical errors that ultimately leads to inappropriate patients diagnosis and treatment.

Prevention of pre-analytical errors including; problems in specimen preparation, centrifugation, aliquot preparation, pipetting, and sorting is required to improve patient safety and the performance of clinical laboratory.

In this study, the pre-analytical errors was observed with 2.07% of all samples collected in the biochemistry laboratory at Hera’a General Hospital from January to December 2014. However, Chawla and colleagues reported a lower percentage (1.52%) of rejection from the clinical chemistry laboratory for errors in the pre-analytical phase during a period of one year [8].

The result of this study showed that the most frequent preanalytical error was the visible haemolysis after sample centrifugation. Haemolysis of samples, that occurs when blood is forced through a fine needle, was also noticed in several studies [12-14] and these previous results matched the findings of our study. In 2010, a study has emphasized that sample’s haemolysis accounted for the majority of rejections at clinical biochemistry lab [8]. Moreover, this observation is similar to 3-5% pre-analytical errors observed by Hawkins in his review [6].

This study also detected an overall specimen rejection rate of 23.72% from emergency department (ED), which might be related to workload and pressured environment in the ED. On the other hand, the lowest percentage of rejected samples was reported from the OPD with 1.8%.

Conclusion

This study reveals that the pre-analytical errors were generated as a result of few causes including; quantity not sufficient (QNS), clotting, visible haemolysis after centrifugation, mismatch and wrong tube. Therefore, this study suggests keeping a record of the errors at all stages of the pre-analytical process and then devising corrective strategies among different department according to the common causes for rejections, for their prevention, which can gradually free a laboratory from such errors. In addition to documentation of rejected samples, the periodic training of healthcare personnel is an essential step in decreasing sample rejection ratios, improving quality of the total testing process in the clinical laboratory and promoting patient-centered health care service.

References

1. Boone DJ (1993) Governmental perspectives on evaluating laboratory performance. ClinChem 39:1461-1467.
2. Carraro P, Plbani M (2007) Errors in a Stat Laboratory: Types and Frequencies 10 Years Later. Clinical Chemistry 53: 1338-1342.
3. Goswamia B, Singha B, Chawla R,Mallika V (2010) Evaluation of errors in a clinical laboratory: a one-year experience. Lab Med 48: 63-66.
4. Astion ML, Shojania KG, Hamil l TR, Kim VL (2003) Classifying laboratory incident reports to identify problems that jeopardize patient safety. Am J ClinPathol 20: 18-26.
5. Plebani M, Piva E (2011) Medical errors: pre-analytical issue in patient safety medicinske,”J Med Biochem 30: 310-314.
6. Hawkins R (2012) Managing the Pre- and Post-analytical Phases of the Total Testing Process. Ann Lab Med 32: 5-16.
7. ZainiRG, Shesha NT (2015) Identification of the Pre-Analytical Errors among Government Hospitals at Makkah, Saudi Arabia. Asian Journal of Research in Biological and Pharmaceutical Sciences3: 133-139.
8. Chawla R, Goswami B, Tayal D, Mallika MD (2010) Identification of the Types of Preanalytical Errors in the Clinical Chemistry Laboratory: 1-Year Study at G.B Pant hospital. Labmedicine 41: 89-92.
9. Plebani M (2006) Errors in clinical laboratories or errors in laboratory medicine? ClinChem Lab Med 44: 750-759.
10. Chhillar N, Khurana S, Agarwal R, Singh N (2010) Effect of Pre-Analytical Errors on Quality of Laboratory Medicine at a Neuropsychiatry Institute in North India. Ind J ClinBiochem26: 46-49.
11. Gree SF (2013) The cost of poor blood specimen quality and errors in preanalytical processes. ClinBiochem 46: 1175-1179.
12. Fidler JR (2007)Task analysis revisited: Refining the phlebotomy technician scope of practice and assessing longitudinal change in competencies. Eval Health Prof30: 150-169.
13. Lowe J, Stike R, Pollac M, Bosley J, O'Brien P(2008) Nursing Blood Specimen Collection Techniques and Hemolysis Rates in an Emergency Department: Analysis of Venipuncture Versus Intravenous Catheter Collection Techniques. Journal of Emergency Nursing34: 26-32.
14. Marin AG, Ruiz R, Pérez-Hidalgo M,Mendoza PM (2014) Pre-analytical errors management in the clinical laboratory: a five-year study. Biochemia Medic 24: 248-257.