Accurate Results in the Clinical Laboratory: A Guide to Error Detection and Correction

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Accurate Results in the Clinical Laboratory: A Guide to Error Detection and Correction
Copyright
List of contributors
Foreword (from the first edition)
	Reference
Preface
Part I: Sources of errors in clinical laboratories: an overview
1 -
Variation, errors, and quality in the clinical laboratory
	Introduction
	Errors in clinical laboratory
	Quality improvement in clinical laboratory
	Conclusions
	References
2 -
Errors in patient preparation, specimen collection, anticoagulant and preservative use: how to avoid such pre-analytical errors
	Introduction
	Biological rhythms and laboratory test results
	Patient preparation
		Fasting
		Body position
	Whole blood, plasma, and serum specimens for clinical laboratory analysis
		Whole blood
		Plasma versus serum specimens
			Sample volume
			Sample preparation time
			In vitro hemolysis
			Specimen composition
	Anticoagulants and preservatives, order of draw, separator tube gel interference and volume
		Plastic and glass tubes
		Surfactants
		Stoppers and stopper lubricants
		Serum separator gel tubes (SST)
		Anticoagulants
	Order of draw of various blood collection tubes
	Collection sites; arterial, capillary, and venous blood samples; collections from catheters and intravenous lines
		Skin puncture
		Venipuncture
		Arterial puncture
		Indwelling catheters and intravenous lines
		Contamination
		Tourniquet effect
		Hemolysis
	Urine collection, timing, and techniques
		Timing of urine collection
		Specimen labeling
		Clean catch specimen
		Catheterization
		Suprapubic aspiration
		Adhesive bags
		Specimen handling, containers, and preservatives
	Conclusions
	Acknowledgments
	References
3 -
Sample processing and specimen misidentification issues: major sources of pre-analytical errors
	Introduction
	Transportation
		Transportation time
		Effects of temperature
		Effects of specimen handling and turbulence
		Shipping to reference laboratory
		Special case: blood gases and ionized calcium
	Effect of centrifugation on test results
	Effect of storage conditions on laboratory results
	Effect of cross-contamination on laboratory results
	Specimen misidentification
	Conclusions
	References
4 -
Effect of patient-related factors on clinical laboratory test results
	Introduction
	Effect of age related changes on clinical laboratory test results
		Prenatal/newborn population
		Childhood to puberty stages
		Adulthood
		Menopausal pre- and post- period
		Elderly
	Gender related changes on clinical laboratory values
	Dietary related changes on clinical laboratory values
		Food ingestion-related changes on clinical laboratory values
		Special diet-related changes on clinical laboratory values
		Fasting/starvation-related changes on clinical laboratory values
		Nutraceutical-related changes on clinical laboratory values
		Cross-sex hormone therapy effects on laboratory test results
	Exercise related changes on clinical laboratory values
	Difference in laboratory test results among populations
	Conclusions
	References
5 -
Interferences of hemolysis, lipemia and high bilirubin on laboratory tests
	Introduction
	Effect of hemolysis on laboratory tests
		In vivo hemolysis
		Case report
		In vitro hemolysis
		Case report
	Lipemia
		Case report
	Icterus
	Methods for evaluating the effect of endogenous interfering substances
	Conclusions
	References
6 -
Immunoassay design
	Introduction
	Immunoassay methods and assay principle
	Immunoassay reagents
	Limitations of immunoassays
	Specimen types for immunoassays
	Conclusions
	References
7 -
Overview of other sources of interferences in immunoassays: prozone effect and interferences from heterophilic antibodies a ...
	Introduction
	Limitations of immunoassays
	Heterophilic antibody interferences
		Mechanism of heterophilic antibody interference
		How problematic is heterophilic antibody interference?
	Interference from auto-antibodies and therapeutic antibodies
		Autoantibodies to the analyte
		Autoantibodies to a component in the reagent
	Interference from human anti-animal antibodies (HAAA)
		Antibodies to other species
	Detection and correction of heterophilic antibody interferences
		Removal of interfering substances
	Prozone effect
	Conclusions
	References
8 -
Biotin interference in clinical laboratory tests: sporadic problem or a serious clinical issue?
	INTRODUCTION
	UTILIZATION OF BIOTIN IN IMMUNOASSAYS
	BIOTIN INTERFERENCE IN IMMUNOASSAYS
		The convergence of susceptible methods and supra-physiological biotin intake
	BIOTIN REQUIREMENT AND PHYSIOLOGICAL FUNCTIONS
		Inborn errors of biotin metabolism
		Acquired biotin deficiency
		High dose biotin therapy in inborn errors of metabolism
		High dose biotin therapy beyond metabolic disease
		Biotin supplementation for skin, hair and nails
		Biotin metabolism and pharmacokinetics
	HISTORY OF BIOTIN INTERFERENCE
	ADVERSE EFFECTS FROM BIOTIN INTERFERENCE
		Assessing the risk of adverse events
	SOLUTIONS TO THE PROBLEM OF BIOTIN INTEFERENCE
		Education and awareness: general and specific approaches
		Responsible medication management: notification of biotin interference
		Notification of biotin use at the time of blood collection
		Surveillance
		Harnessing the pharmacokinetic parameters of biotin
		Depletion of biotin
		Assay re-design to improve biotin tolerance
		Alternative methods
	CONCLUSION
	Acknowledgments
	References
Part II: Sources of errors in clinical chemistry laboratory
9 -
Challenges in routine clinical chemistry testing analysis of small molecules
	Introduction
	Creatinine analysis
		Limitations of the MDRD equation
		Creatinine assay methods
			Jaffe-based methods
				Case reports
			Enzymatic creatinine assays
				Case report
	Urea analysis
		Urea assay methods
	Ammonia assay
		Pre-analytical factors
		Assay methodology for ammonia
	Uric acid analysis
		Analytical considerations for uric acid analysis
			Case report
	Glucose analysis
		Pre-analytical considerations for glucose measurement
		Methodology for glucose testing
		Interferences in glucose assays
			Glucose oxidase
			Hexokinase
			Glucose dehydrogenase
				Case report
	Analysis of electrolytes
		Physiologic pre-analytical issues
		Specimen issues
			Case report
		Analytical issues
			Ion-specific electrodes
		Adjustment for plasma water with indirect methods
		Total CO2
		Calcium assays
		Magnesium assays
		Phosphate Assays
	Blood gases analysis
		Pre-analytical issues
		Analytical issues
	Lactate analysis
		Analytical issues
			Case report
	Bilirubin analysis
		Pre-analytical issues
		Analytical issues
			Case report
	Lipid profiles analysis
		Fasting versus nonfasting lipid profiles
		Other pre-analytical considerations
		Analytical issues
			Case report
	Conclusion
	References
10 -
Challenges in routine clinical chemistry analysis: proteins and enzymes
	Introduction
	Albumin and total protein
		Pre-analytical issues
		Analytical issues and interferences
		Urinary albumin measurements to detect microalbuminuria
	Alanine and aspartate aminotransferases analysis
		Case report
		Specimen processing
		Methodology
	γ-Glutamyl transferase and alkaline phosphatase analysis
		Analytical issues
	Amylase and lipase analysis
		Analytical issues
	Lactate dehydrogenase analysis
	Creatine kinase analysis
	Cardiac troponin analysis
		Analytical issues
	B-type natriuretic peptide analysis
		Pre-analytical considerations
		Analytical issues
	Iron studies
		Emerging markers in iron metabolism
	Conclusions
	References
11 -
Challenges in endocrinology testing
	Introduction
	Pre-analytical considerations
		Sample collection and processing
	Assays for hormonal analysis
		Assay specificity
		High-dose hook effect
		Macro-complexes
		Human anti-mouse antibodies, rheumatoid factor and heterophile antibodies
		Biotin ingestion-associated interference
	Challenges in testing of hormones secreted by pituitary
		Growth hormone
		Adrenocorticotropic hormone
		Thyroid stimulating hormone
		Luteinizing hormone/follicle stimulating hormone
		Prolactin
	Challenges in measuring human chorionic gonadotropin
	Challenges in thyroid function tests
		Thyroglobulin
		Calcitonin
	Adrenal function tests
		Cortisol
		Aldosterone & renin
	Testing of parathyroid function
		Parathyroid hormone
		Assays for 25-hydroxyvitamin D
	Gonadal and reproductive medicine
	Testing for insulin like growth factor-I
	Measurement of other hormones including insulin
	Prenatal testing
	Conclusions
	References
12 -
Pitfalls in testing for common tumor markers
	Introduction
	Clinical application of tumor markers
		Screening and early detection of cancer
		Diagnosis of cancer
		Evaluating prognosis
		Monitoring therapy
		Detecting relapses
	Prostate specific antigen (PSA)
		PSA expression and processing
		Benign prostatic hyperplasia (BPH)
		Elevated PSA in prostate cancer and other conditions
		PSA testing
		Serum free and bound PSA
		Complexed PSA
		Percent [-2]proPSA
		False positive and unexpected PSA results
		Newer urine biomarkers of prostate cancer
	Cancer antigen 125 (CA-125)
		False positive and false negative CA-125
		Emerging biomarkers in diagnosis of ovarian cancer
	Alpha-fetoprotein (AFP)
		False positive AFP
	Carcinoembryonic antigen (CEA)
		Serum CEA concentration and colorectal carcinoma
		Arguments against serial CEA testing
		Frequency of testing
		CEA in cholangiocarcinoma
		False positive CEA
	CA-19-9 (carbohydrate antigen 19-9)
		Combined CEA and CA 19-9
		Pitfalls in measuring CA-19-9
	β2 microglobulin
	Human chorionic gonadotropin
		Causes and evaluation of persistent low levels of human chorionic gonadotropin
		False positive human chorionic gonadotropin
	Markers of breast cancer
	Hetrophilic antibody interference in tumor markers testing
	Less frequently monitored tumor markers
	Conclusions
	References
Part III: Sources of errors in therapeutic drug monitoring and toxicology
13 -
Issues of interferences in therapeutic drug monitoring
	Introduction
	Sources of pre-analytical factors affecting drug levels
	Sources of analytical interferences in TDM
	Mechanisms of analytical interferences in TDM
		Chromatography and mass spectrometry
	Specific examples of interferences that affect TDM
		Interferences in digoxin Measurement
			Pre-analytical variables
			Analytical variables
			Digoxin metabolites
			DLIF (Digoxin like immunoreactive factors)
			Anti-digoxin immune fragments
			Cardiac glycosides
			Aldosterone antagonists
			Herbal medicines
			Case example [44]
	Interferences in carbamazepine measurement
		Pre-analytical variables
		Analytical variables
	Interferences in phenytoin measurement
		Pre-analytical variables
		Analytical variables
			Case example [56]
	Interferences in measurement of immunosuppressants
		Pre-analytical variables
		Analytical variables
			Drug metabolites
			Endogenous interfering substances
			Case example [68]
	Interferences in measurement of antidepressants and mood stabilizers
		Tricyclic antidepressants
			Pre-analytical variables
			Analytical variables
			Case example [77]
		Lithium
			Pre-analytical variables
			Analytical variables
	Conclusions
	References
14 -
Limitations of immunoassays for screening of drugs of abuse in urine: issues of false positive and false negative results
	Introduction
	Issues of specimen adulteration
	Immunoassay interferences
		Amphetamines
		Amphetamine isomers/medications containing or metabolizing to amphetamines
		Interference from over the counter and prescription medication
		Opioids
		Opiates screening assays
		Methadone/EDDP screening
		Fentanyl screening
		Oxycodone screening
		Buprenorphine screening
		Benzodiazepines
		Cannabinoids
	Liquid chromatography combined with mass spectrometry for confirmation
	Conclusions
	References
15 -
Challenges in confirmation testing for drugs of abuse
	Introduction
	Specimen selection
	Purpose of drug testing
	Testing process for drug confirmation
	Confirmation of amphetamines
	Confirmation methods for benzoylecgonine
	Confirmation of opioids
		Heroin
		Morphine
		Codeine
		Hydrocodone
		Hydromorphone
		Oxycodone
		Oxymorphone
		Methadone
		Interpretation of opioid results
	Confirmation of marijuana metabolite
	Confirmation of phencyclidine
	Confirmation of benzodiazepines
	Confirmation of barbiturates
	Specimen validity testing
	Conclusions
	References
16 -
Issues of false negative results in toxicology: difficult in detecting certain drugs and issues with detection of synthetic ...
	Introduction
	Abuse of NPS
		Rise of synthetic cannabinoids, cathinones and fentanyl analogues abuse
	Analytical challenges
		Reference standards for the appropriate analytical target
		Assay sensitivity
		Glucuronidation, hydrolysis, and metabolites
	NPS in various biological matrix
		Urine
		Hair
		Blood
		Oral fluid
	Limitations of NPS immunoassays
	Confirmation of NPS
		Mass spectrometers and library searching
	Conclusions
	References
17 - Ethanol determination using automated analyzers: limitations and pitfalls
	Introduction
	Pharmacodynamics of ethanol
	Pharmacokinetics of ethanol
	Alcohol measurement methods
		Testing methodologies: alcohol oxidase (AOD)
		Testing methodologies: alcohol dehydrogenase (ADH)
	Performance evaluation of enzymatic alcohol assays
		Shortcomings of existing automated testing methods
			Shortcomings of existing automated testing methods: cross reactivity with other alcohols
			Shortcomings of existing automated testing methods: elevated lactate and LDH
	Eliminating interferences in alcohol assays
		Pre-analytical considerations
		Post-analytical considerations
	Markers of ethanol ingestion
		Markers of ethanol ingestion: osmole gap
		Markers of ethanol ingestion: ethyl glucuronide, ethyl sulfate, phosphatidylethanol (PEth) and fatty acid ethyl esters (FAEEs)
		Markers of ethanol ingestion: biochemical abnormalities
	Toxic alcohols
	Conclusions
	References
Part IV: Herbal medicines and laboratory testings
18 -
Effects of herbal supplements on clinical laboratory test results
	Introduction
	Issues with variable active ingredients and poor manufacturing practice of herbal supplements
	FDA warnings to toxic herbs
	Mechanisms by which herbal supplements affect laboratory tests
	Herbal supplements and abnormal liver function tests
		Kava
		Comfrey and coltsfoot
		Germander
		Chaparral
		Pennyroyal
		Green tea extract
		Other supplements associated with liver damage
	Herbal supplements associated with kidney damage
	Herbal supplements and hypoglycemia
		Adulteration of herbal supplements with oral hypoglycemic agents
	Licorice and hypokalemia
	Kelp and abnormal thyroid function tests
	Drug-herb interactions
		Interaction of St. John's wort with various drugs
		Interactions of warfarin with herbal supplements
		Kava-drug interactions
		Drug interactions with ginkgo biloba
		Other drug-herb interactions
	Herbs adulterated with Western drugs
	Grapefruit juice-drug interactions
	Herbs interfering with digoxin immunoassays
	Conclusions
	References
Part V: Sources of errors in immunology laboratory
19 -
Critical issues in hemoglobinopathy detection and serology testing for HIV and hepatitis infections
	Introduction
	Challenges in hemoglobinopathy detection
		Hemoglobinopathy diagnosis errors
	Challenges in HIV testing
		Rapid HIV antibody tests
		Combined antibody antigen tests
		Confirmation tests
	Hepatitis testing
		Serology for hepatitis B
		Serology for hepatitis C
	Conclusions
	References
20 -
Sources of errors in immunology and serology testing
	Introduction
	Detection of monoclonal proteins
		Hypogammaglobulinemia
		Immunofixation studies
		Capillary zone electrophoresis
		Free light chain (FLC) immunoassay
	Cerebrospinal fluid (CSF) electrophoresis
	Antinuclear antibodies
	Conclusions
	References
Part VI: Sources of errors in molecular, genetic and related testings
21 -
Sources of error in molecular diagnostic analyses
	Introduction
	Pre-analytical issues
		Specimen collection
		Specimen storage and transport
		Specimen assessment
		Nucleic acid extraction
	Molecular methods
		Hybridization methods
		Microarrays
		Amplification methods
			Polymerase chain reaction (PCR)
			Strand-displacement amplification (SDA)
			Transcription-mediated amplification methods
			Amplification inhibitors
			Mechanisms of inhibition
			Commonly encountered inhibitors and their sources
			Monitoring for amplification inhibition
			Strategies to prevent inhibition
		Nucleotide sequencing
			Sanger sequencing
			Next-generation sequencing (NGS)
			Case report: incorrect zygosity call for a variant detected by whole exome sequencing
	Common causes of false positive and false negative results
		Sequence mismatch between primer and target DNA: role of genetic variation
			Case report: false negative result of PCR testing for Neisseria meningitidis
		Mispriming/cross reactivity of primers and probes
		Contamination
	Quality management
		Quality control
			Quality control for qualitative assays
			Quality control for quantitative assays
	Conclusions
	Acknowledgments
	References
22 -
Molecular testing for targeted therapies and pharmacogenomics
	Introduction
	Method description
		Targeted single variant detection
		Multi-variant panels
		Sequencing
	Applications of molecular testing
		Targeted therapies for tumor/somatic variant detection
		KRAS
		BCR/ABL
		KIT
		Host factors influencing response to infectious disease
		HLA 5701
		HLA-B∗15:02
	Pharmacogenetics of metabolic enzymes
		CYP2D6
		Hemostasis (CYP2C19, CYP2C9, VKORC1)
	Precision medicine and pediatrics
	Case studies
	Conclusions
	Acknowledgments
	References
23 -
Challenges and sources of inaccuracy in biochemical genetics testing
	Introduction
	Preanalytical challenges
	Analytical challenges
		Method evaluation, quality control and quality assurance
	Post-analytical challenges
	Challenges in the diagnosis of specific disorders
		Amino acids disorders
		Organic acid disorders
		Fatty acid oxidation defects
		Lysosomal storage disorders
	Conclusions
	Acknowledgments
	References
Part VII: Sources of errors in microbiology testings
24 -
Sources of pre-analytical, analytical and post-analytical errors in the microbiology laboratory
	Introduction
	Pre-analytical errors
		Test selection
		Test ordering
		Specimen collection
		Specimen labeling
		Specimen transport
		Specimen storage
		Specimen processing
		Case study
	Analytical errors
		Case study
	Post-analytical errors
		Reporting
	Turnaround time
		Corrected reports
	Results archiving and specimen storage
		Case study
	Quality improvement
	Conclusions
	References
Part VIII: Sources of errors in hematology and coagulation testings
25 -
Sources of errors in hematology testing
	Introduction
	Errors in hemoglobin measurement and RBC count
	Errors in MCV and related measurements
	Errors in WBC counts and WBC differential count
	Errors in platelet count
	Errors in specific hematology testing
		Cold agglutinins
		Cryoglobulins
		Pseudothrombocytopenia
		Spurious leukocytosis
		False positive osmotic fragility test
	Errors related to sample collection, transport and storage
		A case study
	Conclusions
	References
26 -
Sources of errors in coagulation testing
	Introduction
	Errors in PT and PTT measurement
	Errors in thrombin time measurement
		Incorrectly filled tubes
		Dilution or contamination with anticoagulants
		Traumatic phlebotomy
		Fibrinolysis products and rheumatoid factor
		PFA-100/200
	Platelet aggregation testing using lipemic, hemolyzed or specimen collected from a petient with thrombocytopenia
	Thromboelastrography
		Challenges in anticoagulants and lupus anticoagulant tests
		A case study
			Case one
	Conclusions
	References
27 -
Sources of errors in flow cytometry
	Introduction
	Specimen quality
		Cell viability
		Sample transit times
		Clotting, cell clumping and laminar flow
		Cell doublets
		Platelet aggregates
		Paraproteins and flow analysis
		Mab therapies
		Flow cytometry analysis of fluids
	Technological challenges in flow cytometry
		Compensation
		Spillover beyond compensation
		Tandem dyes
		The strange case of calcium oxalate and CSF
	The human factor
		Case scenario 1
		Case scenario #2
	Conclusions
	References
Part IX: Sources of errors in transfusion medicine
28 -
Interferences in blood bank testing
	INTRODUCTION
	ABO TYPING
		RhD typing
		Antibody screen and extended panel
		Autocontrol and direct anti-human globulin test
		In vitro compatibility testing or crossmatch
		RBC phenotype
	INTERFERENCES IN BASIC BLOOD BANK TESTING
		Interferences in ABO/Rh typing
		Weak or absent reactivity of expected antigen
		Unexpected RBC antigen-like reactivity
		Weak or loss of expected antibody
		Unexpected antibody reactivity
		Interferences in the antibody identification
		Case studies
		Case study #1
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #2
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #3
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #4
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #5
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #6
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #7
			Clinical summary and initial testing
			Interpretation
		Case study #8
			Clinical summary and initial testing
			Interpretation
		Case study #9
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation and recommendations
		Case study #10
			Clinical summary and initial testing
			Interpretation
		Case study #11
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #12
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
		Case study #13
			Clinical summary and initial testing
			Initial interpretation and further testing
			Final interpretation
	CONCLUSIONS
	References
29 -
Errors and adverse effects of blood transfusion
	INTRODUCTION
	ERRORS IN TRANSFUSION
	ADVERSE EFFECTS OF TRANSFUSION
		Acute hemolytic transfusion reaction
		Delayed serologic and hemolytic transfusion reaction
		Febrile nonhemolytic transfusion reaction
		Allergic transfusion reaction
		Septic transfusion reaction
		Transfusion associated circulatory overload (TACO)
		Transfusion-related acute lung injury (TRALI)
		Post-transfusion purpura
		Transfusion-associated graft versus host disease
		Hypotension
		Iron overload
		Case study
			Vital signs
			Laboratory results
			Blood bank workup
			Interpretation
	CONCLUSIONS
	References
Part X: Sources of errors in point of care testing
30
	30 -
Methodological issues in point of care testing devices
		Introduction
		Design of POC devices
		Methodological issues of POC devices
			Glucose
			Metabolites
			Drugs of abuse
			Cardiac markers
			Diabetes markers – hemoglobin A1c (HbA1c)
			Pregnancy tests (hCG)
			Multiplexed POC assays
			Infectious disease (ID)
			Blood gas
			Coagulation meters
			Other POC devices
		Guidelines for using POCT devices
		Conclusions
		References
31
	31 -
Special concern: sources of inaccuracy in breath alcohol analysis
		Introduction
		Alcohol analysis using breath analyzers: legal issues
		Alcohol measurement in breath
			Partition of alcohol between blood and alveolar air
			Technical aspect of breath alcohol measurement
		Issues with partition ratio
		Alcohol measurement in breath: cooperative versus noncooperative person
		Lung function and breath alcohol analysis
		Effect of hematocrit and body temperature on breath alcohol analysis
		Sources of errors in breath alcohol measurement
			Case report
			Breath alcohol analysis and GERD
			Interferences of volatiles in breath alcohol analysis
			Case report
		Can alcohol be produced endogenously?
		Conclusions
		References
Index
	A
	B
	C
	D
	E
	F
	G
	H
	I
	J
	K
	L
	M
	N
	O
	P
	Q
	R
	S
	T
	U
	V
	W
	X
	Y
	Z
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