Preface vii
An Introduction, Because Every Book
Should Have One 1
Section One: Finding the Sweet Spot 5
Chapter 1
Bayesian Thinking 7
Chapter 2
Moving the Needle: Sensitivity, Specificity, Predictive Values,
and Likelihood Ratios 9
Chapter 3
Four Things That Matter 17
Understand the Meaning of “Normal” and “Abnormal” 17
Order Only Tests That Will Change or Guide Your Management 18
Consider Cost and Invasiveness 20
Don’t Miss the Big Picture: How Sick Is Your Patient? 20
Section Two: Profiles and Panels: Common Lab
Tests That Come in Families 21
Chapter 4
The Complete Blood Count 23
A Quick Overview 23
The Red Blood Cells 24
The White Blood Cells 34
Platelets 43
Chapter 5
The Comprehensive Metabolic Panel (CMP) 47
Glucose, Electrolytes, and Kidney Function 50
Liver Function Tests 66

Total Protein, Albumin, and Globulins 73
Calcium 76
Chapter 6
The Lipid Panel 82
Chapter 7
Thyroid Function Tests
86
Chapter 8
The Urinalysis 91
Chapter 9
Blood Gases 104
Arterial Versus Venous Blood Gases 105
Oxygenation 106
Lactate 112
CO2 and Ventilation 114
Acid-Base Balance 116
Numbers on a Blood Gas You Can (and Should) Generally Ignore 131
Chapter 10
Cerebrospinal Fluid (CSF) 133
Chapter 11
Pleural Fluid 149
Chapter 12
Peritoneal (Ascitic) Fluid 163
Chapter 13
Synovial Fluid 178
Bonus Chapter: A Few Words About Notation 187
Section Three: Other Tests You Need to
Know 189
Chapter 14
Infectious Diseases 191
Principles of Testing 191
Common Respiratory Pathogens 203

Epstein-Barr Virus 209
Cytomegalovirus 212
COVID-19 216
Tuberculosis 217
Fungal Diseases 222
Human Immunodeficiency Virus 229
Sexually Transmitted Infections 233
Vaginal Discharge 238
Tick-Borne Infections 241
A Few Words About Parasites 247
Childhood Infections 250
Anti-Streptococcal Antibodies: Acute Rheumatic Fever And Post-Streptococcal
Glomerulonephritis 253
Malaria and Other Tropical Diseases 256
Chapter 15
Cardiopulmonary Medicine 264
Cardiac Biomarkers 264
Natriuretic Peptides (B-Type Natriuretic Peptide and Atrial Natriuretic Peptide) 271
D-Dimer 274
Alpha-1 Antitrypsin Deficiency 276
Chapter 16
Gastroenterology 278
Common Stool Studies 278
Celiac Disease 285
Helicobacter Pylori 287
Pancreatitis: Lipase and Amylase 289
Gastrin and Zollinger-Ellison Syndrome 293
Chapter 17
Hepatology 294
Viral Hepatitis 294
Autoimmune and Metabolic Liver Disease 304
Acute Liver Failure, Hepatic Encephalopathy, and Ammonia 309
Chapter 18
Nephrology and Urology 312
Urine Electrolytes 312
Kidney Stones: Metabolic Evaluation 316

Chapter 19
Endocrinology 319
Hyperglycemia, Diabetes, and Hypoglycemia 319
More Thyroid Tests 325
Cortisol and the Hypothalamic-Pituitary-Adrenal Axis 327
The Renin-Angiotensin-Aldosterone System 336
Testosterone, Estrogen, and the Hypothalamic-Pituitary-Gonadal Axis 339
Prolactin 344
Catecholamines and Metanephrines 346
Growth Hormone And Insulin-Like Growth Factor-1 348
17-Hydroxyprogesterone and Congenital Adrenal Hyperplasia 351
Semen Analysis 353
Pregnancy Testing 355
Anti-Müllerian Hormone 357
Markers of Bone Turnover 358
Chapter 20
Hematology/Oncology 360
Iron Studies 360
Vitamin B12 (Cyanocobalamin) And Folate 362
Hemolysis 366
Flow Cytometry 374
Serum Protein Electrophoresis, Urine Protein Electrophoresis,
Serum Free Light Chains, and Immunoelectrophoresis 375
Intrinsic Red Blood Cell Disorders 379
Tests of Hemostasis and Abnormal Bleeding 387
Hypercoagulable Disorders 393
Heparin-Induced Thrombocytopenia 403
Blood Typing 406
Tumor Lysis Syndrome 409
Cancer Screening 410
The Porphyrias 417
Chapter 21
Neurology 419
The Laboratory in Neurologic Disease 419

Chapter 22
Rheumatology 423
Autoimmune Disorders: Principles of Testing 423
Antinuclear Antibodies 436
Rheumatoid Factor and Anti–Cyclic Citrullinated Peptide Antibodies 442
HLA-B27 and Spondyloarthritis 445
Crystalline Arthritis: Gout and Pseudogout 447
Muscle Enzymes and Myositis 450
Vasculitis-Associated Antibodies 456
Erythrocyte Sedimentation Rate and C-Reactive Protein 463
Chapter 23
Toxicology and Therapeutic Drug Monitoring 468
Toxicology 468
Therapeutic Drug Monitoring 477
Chapter 24
Odds and Ends 478
Routine Health Maintenance 478
Preoperative Evaluation 481
The Patient with Multiple Unexplained Symptoms 482
Section Four: Wrapping Things Up 483
Index 485