Quantification of Pre-analytical Quality Indicators in a Clinical Laboratory and Formulating the Lean Six Sigma DMAIC Strategy

Introduction : Quality control of the laboratory has gained increased importance in the present years. 70 % of the errors in the clinical laboratory occur in the pre-analytical phase. With various guidelines to gauge the quality of the laboratory, Six Sigma Metrics remains by far the most difficult benchmark that a laboratory can achieve. We aimed to quantify the performance of the quality indicators of the routine clinical Biochemistry laboratory in the pre-analytical phase in the form of sigma metrics and devise measures and identify steps to decrease the percentage of errors by defining the DMAIC approach. Materials and Methods : One year retrospective data was collected from January, 2020 to December, 2020 from the data entry register and pre-analytical variables were quantified. Defects Per Million and sigma metric were calculated for each pre-analytical indicator. DMAIC approach was applied and post intervention sigma scores for the month of Jananuary, 2021, February, 2021 and March, 2021 were calculated. Results : Postinterventional analysis was done on a month-to-month basis to monitor the trend and also to ensure corrective action can be taken without delay. Out of 5 quality indicators which were quantified, the pre versus post sigma scores (March’21) are as follows: missing location of the patient (Sigma 4 versus 3.6), missing registration number (Sigma 3.7 versus 4.3) and both registration number and location missing (Sigma 3.6 versus 4.0), Homolysed sample (4.2 versus 4.6), insufficient sample volume (sigma 3.9 versus 4.7). Encouraging results in the form of improved Sigma scores were seen in four of the quality indicators except for the fact that the patient location were still missing in the forms and hence warrants continuous monitoring.

Hemólise interfere na mensuração dos biomarcadores plasmáticos de estresse oxidativo em cães / Hemolysis interferes in the measurement of plasma biomakers of oxidative stress in dogs

Considerando que, entre todas as fontes de erro analítico, a hemólise é a mais importante na rotina laboratorial, o presente estudo teve como objetivo investigar o efeito da hemólise in vitro sobre os principais biomarcadores plasmáticos de estresse oxidativo mensurados (BPEO) de cães. Para tal, amostras de sangue total de 19 cães clinicamente saudáveis foram hemolisadas em diferentes graus por ação mecânica. Amostras controle contendo baixa concentração de hemoglobina (Hb) no plasma foram comparadas com quatro graus de hemólise (<0,36; 0,36-0,60; 0,61-1,0; 1,1-4g/L Hb). Imediatamente após a hemólise, foram mensuradas as concentrações plasmáticas de ácido úrico (AU), albumina, bilirrubina, gamaglutamiltransferase (GGT), capacidade antioxidante total (TAC) e concentração de oxidante total (TOC). Os erros relativos causados pelos diferentes graus de hemólises foram calculados e confrontados com o erro total aceitável (ETA) e com o limite de erro permitido (LEP) empregados nos programas de controle de qualidade de exames laboratoriais. Foi observado que mesmo pequeno grau de hemólise gera algum erro analítico não aceitável (ETA e/ou LEP) nos BPEO mensurados, exceto na bilirrubina. Foi possível concluir que a hemólise é um fator limitante para avaliação do estresse oxidativo sistêmico mensurado no plasma, podendo causar erros que potencialmente comprometem o diagnóstico clínico.(AU)

Among all the various sources of analytical error, hemolysis is the most important in the laboratory routine. The present study aimed to investigate the effect of hemolysis "in vitro" on the main plasma biomarkers of oxidative stress (BPEO) dogs. For this purpose, whole blood samples from 19 healthy dogs were hemolyzed in different degrees by mechanical action. Control samples containing low concentration of hemoglobin (Hb) levels in plasma were compared with four degrees of hemolysis (<0.36, from 0.36 to 0.60, 0.61 to 1.0, 1.1 to 4g/L Hb). Immediately after causing hemolysis, plasma concentrations of uric acid (UA), albumin, bilirubin, gamma glutamyl transferase (GGT), total antioxidant capacity (TAC), and total oxidant concentration (TOC) were measured. The relative errors caused by several levels of hemolysis were calculated and compared with the total acceptable error (TAE) and allowed error limit (LEP) by employees in quality control programs for laboratory tests. Even small levels of hemolysis generate unacceptable analytical error (TAE and / or LEP) in BPEO measured, except for bilirubin. Hemolysis is a limiting factor for the assessment of systemic oxidative stress measured in plasma and may cause errors that potentially compromise clinical diagnosis.(AU)

Influence of the Pre-Analytical Specimen Storage Conditions on the Fecal Occult Blood Test Results / 대한진단검사의학회지

BACKGROUND: Korean national cancer screening program selected fecal occult blood test (FOBT) as a primary screening method of colorectal carcinoma in adult > or =50 yr old irrespective of symptom. Notice to pre-analytical errors is especially important for the FOBT because examinees collect and submit their specimens to laboratories by themselves. We examined the influences of the fecal storage temperatures, durations and with or without buffer on the FOBT results. METHODS: Thirty FOBT-positive specimens above 100 ng/mL were used for the study from July to August 2008. Quantitative FOBT was performed with OC-sensors II (Eiken Chemical Co., Japan). Each specimen was divided into 4 groups. Two groups in plastic buffer-free containers were kept either at 4degrees C or room temperature (25-28degrees C), respectively. Another two groups in buffer-tubes were also kept either at 4degrees C or room temperature. Each group was repeatedly examined with same method every 24 hr up to 120 hr. RESULTS: Eleven specimens (36.7%) in buffer-free containers converted to negative results (below the 100 ng/mL) after 24 hr and 17 specimens (56.7%) did after 48 hr at room temperature. Ten specimens (33.3%) in buffer-free containers converted to negative after 48 hr at 4degrees C. Specimens contained in buffer-tubes showed little change; 3 specimens (10.0%) at room temperature and no specimen at 4degrees C showed negative conversions after 48 hr. CONCLUSIONS: Buffer-tube minimizes false negative FOBT results during pre-analytical delay of specimen. The examinees using buffer-free containers need to be educated to hand in their specimens to laboratories as soon as possible.