why is pre analytical phase important

Preanalytical variables include those related to the patient, specimen collection and specimen handling. Van Acker JT, Verstraete AG, Van Hamme MA, Delanghe J. Falsely increased urinary caffeine attributable to contamination by urine test strips. Preanalytical factors that can affect results include: sample This broadly includes: For each of these steps, there are several opportunities for factors to affect the accuracy of the analysis itself. For a long time, analytical and post-analytical phases were deemed important Demonte D, Pucci M, Salvagno GL, Lippi G (2019) Can citrate plasma be used in exceptional circumstances for some clinical chemistry and immunochemistry tests? The preanalytic phase is an important component of total laboratory quality. The specimen is prepared and tested in the analytical phase. For reducing the risk of errors and contamination, commercially available vacuum systems have been developed, allowing direct sample aspiration into a secondary container. the analytical and post analytical phases. Introduction to Analytical Method Development The quality of the reported results could also be influenced by variables in specimen processing. infections) (10,25,43,44) and lower relative density (typically seen in young children). If a mild precentrifugation (1,0003,000 RCF) is applied, cellular components are spun down. In addition to the insurance of correct sampling, the clinical lab should optimize transport and sample preservation. results [20,21]. Comparison of fully automated urine sediment analyzers H800-FUS100 and labumat-urised with manual microscopy. In contrast to casts, epithelial cells and leukocytes, the stabilization of erythrocytes is extremely difficult, probably due to cellular shrinkage following the addition of formaldehyde solutions (25). Finally, formaldehyde is known to lower the pH; hemoglobin, myoglobin (> 50 mg/L) and ethylenediaminetetraacetic acid (EDTA) have an influence on the creatinine determination and the determination of ascorbic acid can become false-positive by similar reducing agents (10). Pre-Analytical Phase - an overview | ScienceDirect Topics Various subphases have been identified in the pre-analytical phase of urinalysis. Fogazzi GB, Verdesca S, Garigali G. Urinalysis: core curriculum 2008. Grzych G, Pekar JD, Maboudou P (2019) Better Glucose Stability in Serum than in Plasma Samples after 12-h Stay at Room Temperature. Analytical Phase - an overview | ScienceDirect Topics metabolite, glucose, presents a classic case where its levels are applications [22]. Correlation between protein:creatinine ratio and 24-hour protein excretion may not be accurate for proteinuria levels > 1 g/L. However, preservatives may affect some chemical properties and alter the appearance of particles. Pre Ukraine war latest: Kyiv makes cluster bombs pledge; Wagner In a recent multicenter study (17), results obtained from first-voided and mid-stream urine samples were compared. Pre-analytical errors can have a significant negative impact that prevents the delivery of quality patient care. Clin Chem. Manual microscopy and flowcytometry show a good agreement, except for casts and yeast-like cells, where flow cytometry is inferior. The pre-analytic testing phase occurs first in the laboratory process. centrifugation, freezing, thawing, aliquoting and sampling) largely determines the analytical process and the over-all quality. In clinical chemistry, collection tubes contain additives that could calls for serious efforts towards minimizing pre analytical errors as Because of the growing importance of (micro)albuminuria in the diagnosis of kidney disease, more attention has been paid to the particular preanalytical aspects of this analyte. The use of boric acid affects a number of test strip reactions. PRE, POST analytical Preanalytical quality improvement: in quality we trust. After centrifugation, the specimen analysis can be performed using glass slides or a counting chamber. The investigation of dysmorphic erythrocytes, in particular acanthocytes, is also important in the diagnosis of glomerular disorders. Cotten SW, Duncan DL, Burch EA, Seashore CJ, Hammett-Stabler CA. Point-of-care analyses are not subject to this delay, but may as well be affected by various analytical issues. Counts of epithelial cells, erythrocytes and leukocytes, but not for casts were significantly higher in the first-voided samples. Acta Clin Belg 65(5): 311-318. In addition, coloured urine and prophobilinogen can result in false-positive reactions. The introduction of new technologies and automation has improved the accuracy and productivity of the process (4). patient characteristics, sample collection and sample processing. Lippi G, Becan-McBride K, Behlov D, Bowen RA, Church S, Delanghe J, et al. A lower sensitivity is observed after the intake of large amounts of ascorbic acid, in the presence of a high nitrite concentration or after the exposure to light (10,34). variables, sample collection and processing (Figure 1). In summary, measurement of pre analytical errors in medical biology. The European Workplace Drug Testing Society (58), the Substance Abuse and Mental Health Services (59), the Swiss Working Group for Drugs of Abuse Testing Guidelines (60), the Joint Technical Committee (61) and the United Kingdom (62) proposed some criteria for urine validity testing based on several parameters: urinary creatinine concentration, specific gravity, nitrite, pH and presence of exogenous or endogenous substances. Sample preparation is more essential for different particle analysis techniques in comparison with urine test strip analysis and microbiological culture. Counting of native urine avoids the errors created by centrifugation; this procedure lowers the analytical sensitivity. Clinical and Laboratory Standards Institute. FOIA Unexpected interference of baby wash products with a cannabinoid (THC) immunoassay. Clin Chem Lab Med CCLM 56(3): e65-68. errors [12,24,25]. False-positive reactions for ketones or ketone bodies are seen in (a) urine samples with a low pH and a high specific gravity, in (b) urine containing a high amount of levodopa metabolites, (c) in the presence of compounds with sulfhydryl groups (e.g. The volume of urine sediment examined is determined by standardized molded plastic commercial slides and microscopic optical properties. hemolysis [3,4] or leukocyte lysis that could be related to the type Clin Chem Lab Med CCLM. Metabolites 9(5): 99. The post-analytical phase is the final phase of the total testing process and involves evaluation of laboratory test results; release of test results in a timely manner to Kouri TT, Gant VA, Fogazzi GB, Hofmann W, Hallander HO, Guder WG. Morphological erythrocyte analysis remains a separate component of urine particle analysis. For that reason we have presented guidelines for a correct preanalytical management of urine samples in a flowchart (Figure 1). Preanalytical requirements of urinalysis - PMC - National Center designs in metabolomics studies that carefully consider patient Post-Analytical Phase - an overview | ScienceDirect Topics Hence, preparing a separate non-refrigerated aliquot is necessary if differentiation of urinary crystals is requested. However, the erythrocyte count and the percentage of nonlysed erythrocytes in vacuum tubes were lower than in conventional urine tubes (minimum 20% and 31% reduction) in samples with low conductivity. However, contamination with strong oxidizing cleaning agents peroxide or hydrochloric acid can result in a false-positive reaction. that sufficient rigor be applied to ensure robust experimental study of highly unstable and dynamic biomolecules, metabolites Eisinger SW, Schwartz M, Dam L, Riedel S. Evaluation of the BD Vacutainer Plus Urine C&S Preservative Tubes Compared With Nonpreservative Urine Samples Stored at 4{degrees}C and Room Temperature. Failures to consider these Hara F, Shiba K. Nonspecific binding of urinary albumin on preservation tube. It is imperative Pre analytic and postanalytic test management concentrations that could complicate medical interpretation and Pre analytical phase is Interpretation of test results is only possible when these conditions are fulfilled. If persistently positive results for blood are found, clinicians should confirm the presence of erythrocytes in urine by a microscopic sediment analysis. Kouri TT, Vuotari L, Pohjavaara S, Laippala P. Preservation of urine for flow cytometric and visual microscopic testing. Porter IA, Brodie J. Boric acid preservation of urine samples. In leukocyturia or tubular damage (e.g. Current issues in measurement and reporting of urinary albumin excretion. The blood sample process can be divided into three phases: pre-analytical, analytical and post-analytical phases, where errors in pre-analytical phases represent up to 70% . An official website of the United States government. Web1. As urine metabolomics has become a hot topic, the European Consensus Expert Group Report has published a number of recommendations for biobanking procedures (67). As more effort needs to be spent in the preanalytical phase for the further reduction of errors (9), in the present paper we give an overview of the preanalytical challenges of urinalysis. (2019) Transport par pneumatique et fausse hyperkalimie par leucocytose: une tude r Ann Biol Clin (Paris) 77(3) : 281-286. Ample emphasis must be placed on standardization of sample Using automated methods for some brands of reagent strips, falsely elevated urinary glucose test strip results can also be caused by elevated urobilinogen concentrations (34). showed that a 24-hour urine sample was not properly collected in more than half of the informed outpatients, which were often older (mostly > 65 years) and suffering from a chronic disease. An advantage of using a counting chamber is a larger urine volume that can be examined, allowing a more precise analysis. Lee JE, Kim YY (2017) Impact of Preanalytical Variations in Blood-Derived Biospecimens on Omics Studies: Toward Precision Biobanking? When counting equal ranges of particles, microscopy is generally inferior to automated methods (50,53). captopril) or in (d) highly pigmented urine samples (34). Several reports highlight contamination of the sample by glycine (2), iodine (30), caffeine (31) and other constituents of the test strip, which leads to unnecessary further investigation. Grzych G, Roland E, Lezier D, Beauvais D, Maboudou P, et al. Indeed, metabolomics is the A concentrated sample using a glass slide is proposed if manual evaluation is requested. high quality, reproducible experimentation and data generation. Introduction Preanalytical phase is nowadays recognized as the most vulnerable part of the total testing process. Addition of polyethylene glycol (20 g/L) to the ethanol fixative (Saccomannos fixative) improves preservation quality (10,25). Joe Biden is arriving in the UK later for a two-day visit designed to "strengthen" the relationship between the two nations. In particular, laboratories should focus on the analytical test quality, as more reliable results ask for stricter pre-analytical demands. analytical. The reduction of cast counts depends on the vacuum during aspiration (19). A 20% reduction of the number of false positive urine cultures can be achieved by washing the glans penis of men or the introitus of women (10,13,14). Informing the patient goes far beyond only explaining the practical aspects of urine sampling. If commercially available preservatives are used, their influence on chemical properties and appearance of particles should be kept in mind. In comparison with random urine testing, the examination of chemical analytes is more reliable when timed sampling is used, which is however prone to pre-analytical errors. Analytical method development and validation is tremendously important for any drug development program. Check out a sample Q&A here See Solution Knowledge Booster Learn more about A more general use of this time-consuming test is hampered by the lack of unequivocal criteria for identification and quantitation of dysmorphic erythrocytes and the special training (phase contrast microscopy) needed for this examination (45). Simple particle differentiation without staining or phase contrast is not enough for renal elements. Preanalytical phase for transfusion medicine metabolomics studies and also promote better data sharing Besides the analysis of medical samples, some additional requirements are prescribed for forensic specimens: (a) storage of the sample in the original container, (b) minimization of the number of freeze/thaw cycles to reduce specimen degradation, (c) use of control measures to ensure specimen integrity and (d) recordkeeping using internal and external chain-of-custody systems (57). Martinello F, Da Silva EL (2006) Ascorbic acid interference in the measurement of serum biochemical parameters: In vivo and in vitro studies. Pre Mostly, microscopy is used for a rough estimate of the amount of figurated elements. Unfortunately, a universal preservative that allows a complete urinalysis does not (yet) exist. Brandt R, Guyer KE, Banks WL., Jr Urinary glucose and vitamin C. Court JM, Davies HE, Ferguson R. Diastix and ketodiastix: a new semiquantitative test for glucose in urine. Automation of Urine Sediment Examination: a comparison of the Sysmex UF-100 Automated Flow Cytometer with Routine Manual Diagnosis. Pre Urine samples with a high concentration of ascorbic acid, with a high specific gravity, with a low pH ( 6) or with an abnormally high urobilinogen concentration will reduce the test sensitivity (34). In function of the required testing, a difference in preservative demands is requested. Contamination of urine with vaginal discharge/mucus or the intake of some drugs (nitrofurantion, clavulanic acid, meropenem and imipenem) can lead to mis-interpretation. Rasoulpour M, McLean RH, Raye J, Shah BL. Protein and albumin-to creatinine ratios in random urines accurately predict 24 h protein and albumin loss in patients with kidney disease. Grzych G, Pekar JD, Durand G, Deckmyn B, Maboudou P, et al. As modern urinalysis (flow cytometry, automated microscopy) is characterized by a low CV, preanalytical aspects of urinalysis are of growing importance. For the maintenance of the metabolome, time between collection and processing and the temperature at which urine specimens are kept during this time delay should be reduced (68). WebThe pre-analytic phase of the Total Testing Process (T.T.P) begins with the encounter between the clinician and the patient,and includes verification of identity, specimen For maintaining the original urine metabolome, the following procedures for optimal processing and management have been proposed: (i) the combined use of a mild pre-centrifugation (RCF between 1,000 and 3,000 at 4 C) and filtration should remove cells and particulate matters; (ii) samples should be stored long-term in liquid nitrogen to avoid destruction of residual cells; (iii) fast processing; (iv) storage at 4C between collection and processing. Why Pre-Analytical Procedures are Important in Laboratory Testing Doctors use laboratory test results to make final decisions on the diagnosis and treatment Urine drug testing in the clinical laboratory; Approved guideline NCCLS/CLSI T/DM8-A. Br J Haematol. Additional requirements may be needed in function of diagnostic procedures (e.g. Fundamentals of Urine and Body Fluid Analysis. The exact sampling time and delays exceeding the specified limits should be documented. Preanalytical requirements of urinalysis Only a preservative stabilizing both bacteria and urinary particles can be considered as a valid alternative for sample refrigeration. such as calcium influenced by internal pH and albumin An identification and laboratory data system should be implemented; the condition of seals, shipping cartons, specimen containers and urine specimens should be checked for integrity; the information on the specimen requisition form and the external chain-of-custody form should be reviewed for completeness and accuracy (57). Pre-analytical Grzych G, Lopez B, Pekar JD (2019) Increased Triglycerides in a Child. Vitamin C intake, proteinuria (> 5 g/L), glucosuria (> 20 g/L), 1% boric acid, trypsin inhibitor, oxalate or mercuric salts may decrease the sensitivity of the test (10,34,41). The correct preservative to specimen ratio should be respected when samples are preserved for transport and analysis (8). WebAnalytical Phase. Evaluation of the Sysmex UF-100 automated urinalysis analyzer. In pediatric specimens kept at room temperature, a rapid decrease in the white blood cell count was observed (42). sharing sensitive information, make sure youre on a federal Belgium. Need multiple seats for your university or lab? are currently essential in medical biology but it should also be
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