Understanding the concepts associated with variability of laboratory results would help laboratorians improve the quality of laboratory service as well as aid the drive towards harmonization of laboratory quality practices.
In the era of modern technology, health care delivery system involves so many different personnel and specialties that the caregiver must have an understanding and working knowledge of other professional endeavors, including the role of diagnostic evaluation.
Basically, laboratory and diagnostic tests are tools by and of themselves, they are not therapeutic.
In conjunction with a pertinent history and physical examination, these tests can confirm a diagnosis or provide valuable information about a patient status and response to therapy.
In addition to these, laboratory findings are essential for epidemiological surveillance and research purposes.
If the entire network of a laboratory service is to be effectively utilized and contribute to health care and disease prevention, every member of its work force need to:
Understand the role of the laboratory and its contribution to the nation’s health service;
Appreciate the need to involve all members in the provision of health service;
Follow professional ethics and code of conduct;
Experience job satisfaction and have professional loyalty.
Medical laboratory science is a complex field embracing a number of different disciplines such as
Microbiology,
Hematology,
Clinical Chemistry,
Urinalysis,
Immunology,
Serology,
Histopathology,
Immunohematology and
Molecular biology and others
Preanalytical quality control practices in clinical laboratoryDr. Rajesh Bendre
Preanalytical variables contribute maximally to lab errors. However, these variables are most difficult to control as they include human dependency for phlebotomy skills & pretest patient conditioning. Quantifying & monitoring these variables is also more challenging. Use of checklists, continuous training, competency assessments, internal audits & clinician education for appropriate test utilization form some of the tools for improving the preanalytical processes.
In the era of modern technology, health care delivery system involves so many different personnel and specialties that the caregiver must have an understanding and working knowledge of other professional endeavors, including the role of diagnostic evaluation.
Basically, laboratory and diagnostic tests are tools by and of themselves, they are not therapeutic.
In conjunction with a pertinent history and physical examination, these tests can confirm a diagnosis or provide valuable information about a patient status and response to therapy.
In addition to these, laboratory findings are essential for epidemiological surveillance and research purposes.
If the entire network of a laboratory service is to be effectively utilized and contribute to health care and disease prevention, every member of its work force need to:
Understand the role of the laboratory and its contribution to the nation’s health service;
Appreciate the need to involve all members in the provision of health service;
Follow professional ethics and code of conduct;
Experience job satisfaction and have professional loyalty.
Medical laboratory science is a complex field embracing a number of different disciplines such as
Microbiology,
Hematology,
Clinical Chemistry,
Urinalysis,
Immunology,
Serology,
Histopathology,
Immunohematology and
Molecular biology and others
Preanalytical quality control practices in clinical laboratoryDr. Rajesh Bendre
Preanalytical variables contribute maximally to lab errors. However, these variables are most difficult to control as they include human dependency for phlebotomy skills & pretest patient conditioning. Quantifying & monitoring these variables is also more challenging. Use of checklists, continuous training, competency assessments, internal audits & clinician education for appropriate test utilization form some of the tools for improving the preanalytical processes.
In the continuous quality journey, Controlling laboratory Errors is an integral part & focusing on analytical, post-analytical process is the first step. Developing a reporting culture followed by thorough analysis and implementation of appropriate corrective, preventive actions is required.
A lecture for first-year students at Baquba Technical Institute belongs to Middle Technical University. This lecture is a part of the first semester's modules (Medical Laboratory Technology: MLT112).
This lecture included an introduction to medical (or diagnostic) laboratories.
Xmatrx Infinity is a fully automated molecular pathology workstation designed to accelerate life sciences research and drug discovery and development. It is an open system that allows simultaneous optimization of 40 assay parameters in a single run. The 40 independently thermal cyclable workstations enable any slide-based staining assays, including IHC, ISH, CISH, FISH, multiplexing and co-detection, special stain, in situ PCR and miRNA. The Infinity system adapts and completely automates any manual protocols such as denaturation, hybridization, stringency washes, counter stain and final coverslip to maximize testing capacity, minimize hands-on time and ensure consistent results every time.
Hematology is the branch of medicine, that is concerned with the study of blood, blood forming organs and blood diseases. It includes study of etiology, diagnosis, treatment, prognosis and prevention of blood diseases .
After the completion of this presentation we will know about:
What is hematology and its purpose.
hematology laboratory.
Blood and its compositions and collections
Hematology lab equipment's
Some hematological tests , disease and hazards too.
Quality control (QC) is a procedure or set of procedures intended to ensure that a manufactured product or performed service adheres to a defined set of quality criteria or meets the requirements of the client or customer. QC is similar to, but not identical with, quality assurance (QA).
QC IN clinical biochemistry labs and hospitals
In the continuous quality journey, Controlling laboratory Errors is an integral part & focusing on analytical, post-analytical process is the first step. Developing a reporting culture followed by thorough analysis and implementation of appropriate corrective, preventive actions is required.
A lecture for first-year students at Baquba Technical Institute belongs to Middle Technical University. This lecture is a part of the first semester's modules (Medical Laboratory Technology: MLT112).
This lecture included an introduction to medical (or diagnostic) laboratories.
Xmatrx Infinity is a fully automated molecular pathology workstation designed to accelerate life sciences research and drug discovery and development. It is an open system that allows simultaneous optimization of 40 assay parameters in a single run. The 40 independently thermal cyclable workstations enable any slide-based staining assays, including IHC, ISH, CISH, FISH, multiplexing and co-detection, special stain, in situ PCR and miRNA. The Infinity system adapts and completely automates any manual protocols such as denaturation, hybridization, stringency washes, counter stain and final coverslip to maximize testing capacity, minimize hands-on time and ensure consistent results every time.
Hematology is the branch of medicine, that is concerned with the study of blood, blood forming organs and blood diseases. It includes study of etiology, diagnosis, treatment, prognosis and prevention of blood diseases .
After the completion of this presentation we will know about:
What is hematology and its purpose.
hematology laboratory.
Blood and its compositions and collections
Hematology lab equipment's
Some hematological tests , disease and hazards too.
Quality control (QC) is a procedure or set of procedures intended to ensure that a manufactured product or performed service adheres to a defined set of quality criteria or meets the requirements of the client or customer. QC is similar to, but not identical with, quality assurance (QA).
QC IN clinical biochemistry labs and hospitals
Basic QC Statistics - Improving Laboratory Performance Through Quality Contro...Randox
Randox Quality Control's latest educational guide examines Internal Quality Control, External Quality Assessment, Why laboratories should run QC, How often laboratories should run QC, Basic QC statistics and the quality control process.
Biological variation as an uncertainty componentGH Yeoh
To assist the clinical interpretation of a test result, there is a necessity to have an additional non-analytical component in the overall estimation of UM, namely the biological variation.
This content is suitable for medical technologists/technicians/lab assistants/scientists writing the SMLTSA board exam. The content is also suitable for biomedical technology students and people also interested in learning about test methodologies used in medical technology. This chapter describes test quality assurance (QA) and quality control (QC). Please note that these notes are a collection I used to study for my board exam and train others who got distinctions using these.
Disclaimer: Credit goes to those who wrote the notes and the examiners of each exam question. Please use only as a reference guide and use your prescribed textbook for the latest and most accurate notes and ranges. The material here is not referenced as it is a collection of pieces of study notes from multiple people, and thus will not be held viable for any misinterpretations. Please use at your own discretion.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
2. “Every laboratory result is erroneous; it is the degree
that counts”.
A true result could be therefore regarded as an abstract
ideal with an error of zero.
3. Repeating the same test on the same specimen under
the same conditions would not give the same result for
all the repetitions even when the process is performed
under optimal conditions.
An increase in this inherent variability of results
beyond specific limits is what signifies the occurrence
of an unacceptable error within the system of the
testing process.
4. The concept of variation of processes was brought to
the attention of industry by the works of Walter
Shewart and Edward Deming[1].
Chance/Common causes: due to consistent factors
causing predictable variation within a process.
Assignable/Special causes: due to erratic factors
causing unpredictable variation within a process.
Deming advised the complete eradication of special
causes and the continuous improvement of the process
by reducing as much as possible the common
causes[2].
5. Variation in the laboratory could be pre-analytical,
analytical, and post-analytical.
Analytical variation is that which is associated with the
actual analysis of analytes, preanalytical variation is
that due to factors prior to analysis, post-analytical
variation: after analysis.
6. Variability estimates may be used in the clinical
chemistry laboratory for:
the establishment of quality goals or performance
specifications for test methods,
comparison of successive patient’s results,
determining the utility of established reference
intervals,
establishing quality control protocols, and
assessing the clinical utility of laboratory tests[3].
7. Some important concepts related to analytical variation
in the laboratory as defined in the International
Vocabulary of Metrology include[4]:
Random error: Component of measurement error that
in replicate measurements varies in an unpredictable
manner.
Precision: Closeness of agreement between
indications or measured quantity values obtained by
replicate measurements on the same or similar objects
under specified conditions (Measurement precision is
usually expressed numerically by measures of
imprecision, such as standard deviation, variance, or
coefficient of variation under the specified conditions
of measurement). Imprecision is an estimate of
random error.
8. Systematic error: Error component of measurement
error that in replicate measurements remains constant
or varies in a predictable manner.
Bias: An estimate of a systematic measurement error.
Accuracy: Closeness of agreement between a
measured quantity value and a true quantity value of a
measurand.
Trueness: Closeness of agreement between the average
of an infinite number of replicate measured quantity
values and a reference quantity value.
9. Broader concepts of variability
BIOLOGICAL VARIATION:
Biological variation of analytes occurs due to the natural
fluctuation of body fluid constituents around a
homeostatic set point in turn due to variation of
natural factors e.g. changes in sunlight intensity,
humidity, temperature, diet and other natural
phenomena.
There are two components of biological variation:
within-subject biological variation: natural variation
in levels of an analyte in the same healthy individual,
between-subject biological variation: natural variation
in the levels of an analyte in different healthy
individuals.
10. The within- and between-subject components of
variation are expressed in coefficients of variation (CVi
and CVg), respectively.
Biological variation data is used to establish
performance goals:
Three levels of performance are specified for analytical
variability according to the degree of their effects on
test results: ‘Optimal’, ‘Desirable’, and ‘Minimum’,
performance.
Generally, analytical variation should be low in
addition to the biologic variation for a given test for
good performance.
11. Total Analytic Error(TAE) of an analytical method
must be less than the Allowable Total Error(ATE) for
the analyte in question to satisfy performance goals.
Total analytic error(TAE) is derived via method
validation.
Allowable total error is derived from biological
variation data.
13. For example,
Desirable performance specification for a method:
Bias should not exceed 0.25(CVi2 + CVg2)1/2
and
Imprecision should not exceed 0.5 CVi.
(Cvi and CVg are intra- and inter-individual biological
variation respectively).
Hence, for a given analyte;
ATE ≤ 0.25(CVi2 + CVg2)1/2 + k*0.5CVi.
where k = 1.65 at α = 0.05(one sided test at 95%
confidence interval)
For desirable performance, TAE of a method should not
exceed the estimated ATE above.
15. TOTAL ANALYTIC ERROR (TAE):
A concept introduced into analytical chemistry by
James O. Westgard in 1974[5].
It is a comprehensive analytical metric that may be
used to describe the performance of a method.
It incorporates measurements of a method’s
systematic and random error, (or bias and imprecision
respectively) into a single metric.
16. Bias of a method could be estimated via a recovery
experiment or a comparison of methods experiment
amongst others.
Imprecision is measured with the precision
experiment.
18. . Graphical representation of the TAE: Total Analytic
error. SE: Systematic Error, RE: Random Error, SD:
Standard Deviation
19. TAE in its attempt to capture all inherent variation in
the analytic process is similar to the concept of
measurement uncertainty
TAE has also been used for the calculation of a quality
index known as the Sigma Metric.
20. SIGMA METRIC
The sigma metric is a quality index adapted from the
six sigma(6σ) methods that have revolutionalized the
manufacturing and service industries[8–10]
A 6σ production method has specified tolerance limits
that can accommodate variation of up to six standard
deviations from the mean; corresponding to maximal
error rates of four defects per million units produced.
21. Sigma metric based quality control was developed for
the clinical laboratory by James O. Westgard[11]
aiming to have laboratory methods perform at
standards similar to those of the manufacturing
industry.
The sigma metric(SM) of an analytical method is
calculated from the TEA as follows:
SM = (TAE% – Bias%) / CV.
22. The Sigma metric has been adapted for use in quality
control measures that are available as computer
software for laboratories that want to optimize their
quality control practices.
23. MEASUREMENT
UNCERTAINTY(MU)
A recent measure of test method performance in
clinical chemistry.
“The laboratory shall determine measurement
uncertainty for each measurement procedure in the
examination phase used to report measured quantity
values on patients’ samples. The laboratory shall
define the performance requirements for the
measurement uncertainty of each measurement
procedure and regularly review estimates of
measurement uncertainty”[27]: ISO 15189
24. “Parameter, associated with the result of a
measurement, that characterizes the dispersion of the
values that could reasonably be attributed to the
measurand”[28]: GUM 2008.
“A non-negative parameter characterizing the
dispersion of the quantity values being attributed to a
measurand, based on the information used”: VIM 2012.
25. Measurement Uncertainty can be expressed with
individual results issued by the laboratory.
E.g. RBG: (5.8 ± 0.2) mmol/l, where 0.2 is the
measurement uncertainty.
The measurement uncertainty model is more inclusive
of the whole testing process but setback by the relative
complexity of its estimation[33-35].
Schema for estimating measurement uncertainty:
26.
27. REFERENCE CHANGE VALUE (RCV)
utilizes knowledge of analytical and biological
variation to estimate acceptable difference between
two successive results of the same patient.
A ‘normal’ change between two successive results
should not exceed the combined total
variation(analytical and biological) for each result.
28. Variability of first result - Z*(CVa2+ CVi2)1/2
Variability of second result - Z*(CVa2+ CVi2)1/2
Total variation [root sum of squares] = [Z 2*(CVa2+
CVi2) + Z 2*(CVa2+ CVi2)]1/2
Therefore, RCV = 2½*Z*(CVa2+ CVi2)½
where Z = 1.96 at 95% level of significance (two sided
test), and CVa: analytical variation [of the method]
and Cvi: within subject biological variation [of the
analyte].
29. RCV can be referred to as a means of post-analytical
quality control.
30. INDEX OF INDIVIDUALITY
a measure of the degree of ‘within subject variation’
against ‘between subject variation’ expressed as
CVi/CVg.
An analyte with a high index of individuality has
greater dispersion within the individual; hence
established reference intervals are likely to include all
normal test results for a given individual.
Analytes with a low index of individuality vary less
within the individual and reference intervals may not
cover extreme but normal test results returned for an
individual.
31. The RCV may be required to appropriately interprete
the result in such a situation.
32. Conclusion
Understanding the concepts associated with variability
of laboratory results would help laboratorians improve
the quality of laboratory service as well as aid the drive
towards harmonization of laboratory quality practices.