Clinical Chemistry Exam Review Flashcards

Vocabulary practice flashcards covering equipment, quality control, laboratory mathematics, statistics, instrumentation, analytes, clinical enzymology, endocrinology, and toxicology from Clinical Chemistry study notes.

Borosilicate glass

Silica-containing glass material that tolerates heating and sterilization for lengthy periods; common commercial brands include Pyrex and Kimax.

Flint glass

Inexpensive soda lime glass made of silicon, calcium, and sodium oxides commonly used for disposables; releases alkali which can cause laboratory errors.

Volumetric pipette

The most accurate transfer pipette designed with a single calibration mark, calibrated to deliver (TD/SD), and used for nonviscous samples and standards.

Blow-out pipette

A pipette indicated by etched rings near the top mouth piece, requiring the last remaining drop of liquid in the tip to be blown out into the receiving vessel.

Air displacement micropipette

A micropipette mechanism using suction to draw liquid into a disposable polypropylene tip, maintaining an air cushion between the piston and sample.

Positive displacement micropipette

A micropipette mechanism where the reusable integrated piston comes into direct contact with the liquid sample, recommended for highly viscous, dense, or volatile samples.

Horizontal bucket centrifuge

A centrifuge type where tubes attain a horizontal position during rotation and a vertical position at rest, operating up to speeds of about $3000\,rpm$ and producing a flat sediment.

Ultracentrifuge

A high-speed refrigerated centrifuge used to separate layers of different specific gravities, operating at speeds up to $100,000\,rpm$ or $165,000\,g$.

Type I Reagent Water

The purest classification of reagent water, prepared by two or more purification processes, used for standard preparation, trace analysis, and high-accuracy procedures.

Biological Safety Cabinet Class III

A completely enclosed, gas-tight negative-pressure chamber equipped with glove ports and HEPA/ULPA filtration, recommended for handling BSL-4 organisms.

Threshold Limit Value (TLV)

The allowable chemical exposure concentration limit for an 8-hour work shift, which is inversely proportional to chemical toxicity.

Coefficient of Variation (CV)

A measure of spread defined as standard deviation divided by the mean multiplied by $100$, representing the best statistical indicator of analytical precision.

Diagnostic sensitivity

The ability of a test to detect a specific disease or condition, calculated as $\frac{TP}{TP + FN} \times 100$.

Diagnostic specificity

The ability of a test to correctly identify the absence of a specific disease or condition, calculated as $\frac{TN}{TN + FP} \times 100$.

Delta Check

A quality assurance algorithm comparing a patient's current laboratory result with their previous result to detect pre-analytical or analytical errors.

Random error

An unpredictable laboratory error due to chance that affects precision and impacts isolated control observations or individual samples.

Systematic error

An error that influences analytical results consistently in one direction, affecting accuracy across all samples in a run until resolved.

Westgard Rule 13s

A quality control rejection rule triggered when a single control observation exceeds the mean by more than $\pm 3SD$, detecting random error or severe imprecision.

Westgard Rule 22s

A quality control rejection rule triggered when two consecutive control observations exceed the same $\pm 2SD$ limit in the same direction, detecting systematic bias.

Beer's Law

A principle stating that analyte concentration is directly proportional to absorbed light ($A = abc$) and inversely proportional to the logarithm of transmitted light.

Fluorometry

An analytical technique measuring light emitted by excited molecules, offering up to a thousand-fold increased sensitivity compared to standard spectrophotometry.

Quenching

Any undesirable reduction in fluorescence intensity caused by prolonged UV exposure, elevated temperature, pH changes, or interfering contaminants.

Insulin

The sole hypoglycemic hormone, synthesized by pancreatic islet beta cells, which lowers blood glucose by promoting cellular uptake, glycolysis, glycogenesis, and lipogenesis.

Whipple's triad

The diagnostic criteria for hypoglycemia consisting of hypoglycemic symptoms, low plasma glucose concentration ($<50\,mg/dL$), and prompt symptom relief upon glucose administration.

HbA1c

Glycosylated hemoglobin formed by glucose irreversibly binding to N-terminal valines of beta chains, providing an index of average blood glucose levels over 2 to 3 months.

Fructosamine

Glycosylated albumin measured in serum to monitor average glycemic control over the preceding 2 to 3 weeks when HbA1c testing is unreliable.

Hexokinase method

The reference enzymatic method for glucose measurement, utilizing G6PD to measure an increase in NADPH absorbance at $340\,nm$.

Von Gierke disease

Type Ia glycogen storage disease caused by glucose-6-phosphatase deficiency, presenting clinically with hypoglycemia, ketonuria, lactic acidosis, dyslipidemia, and hyperuricemia.

Apolipoproteins

Protein moieties located on the surface of lipoprotein particles that maintain structural stability, act as enzyme cofactors or inhibitors, and serve as cell receptor ligands.

Chylomicrons

The largest, least dense lipoproteins containing $86\%$ exogenous triglycerides, synthesized in the small intestine, and responsible for producing a floating creamy layer in standing plasma.

LDL (Low-Density Lipoprotein)

The primary cholesterol-rich lipoprotein transporting endogenous cholesterol to peripheral tissues; elevated levels are strongly associated with atherosclerosis.

HDL (High-Density Lipoprotein)

A protein-rich lipoprotein synthesized in the liver and intestine that mediates reverse cholesterol transport, removing excess cholesterol from peripheral tissues.

Friedewald equation

Formula estimating LDL cholesterol: $\text{LDL} = \text{TC} - (\text{HDL} + \frac{\text{TG}}{5})$ in $mg/dL$, valid only when triglyceride concentrations are below $400\,mg/dL$.

Abetalipoproteinemia

An autosomal recessive disorder caused by MTTP gene mutations, resulting in a complete absence of Apo B-containing lipoproteins (Apo B-48 and Apo B-100).

Azotemia

An elevated concentration of blood urea nitrogen and other nonprotein nitrogenous compounds, categorized into prerenal, renal, and postrenal etiologies.

Creatinine

A nonprotein nitrogen waste product formed from muscle creatine at a constant rate, excreted by glomerular filtration without tubular reabsorption, serving as a primary marker for GFR.

Jaffe reaction

A classic colorimetric method for creatinine determination based on reaction with alkaline picrate to form a red-orange complex, susceptible to interferences from plasma chromogens.

Cystatin C

An endogenous low-molecular-weight serum marker for GFR that is freely filtered, completely reabsorbed, and catabolized by proximal tubules without dependence on muscle mass or diet.

Lesch-Nyhan syndrome

An X-linked inborn error of purine metabolism caused by complete deficiency of HGPRT, resulting in severe hyperuricemia, neurological symptoms, and orange sand in infant diapers.

Biuret method

A colorimetric total protein assay based on cupric ions reacting with peptide bonds in an alkaline solution to produce a violet-colored complex.

Cardiac Troponins

The gold standard regulatory protein markers (cTnT and cTnI) for diagnosing acute coronary syndrome, demonstrating high cardiac tissue specificity and long-lasting serum elevation.

B-type natriuretic peptide (BNP)

A cardiac neurohormone secreted by myocardial ventricles in response to volume expansion and pressure overload, serving as a diagnostic marker for congestive heart failure.

Conjugated bilirubin (B2)

The water-soluble, polar form of bilirubin synthesized in hepatocytes via UDPGT, which reacts directly with diazo reagent without an accelerator and is excretable in urine.

Gilbert syndrome

A benign liver disorder characterized by hepatic unconjugated hyperbilirubinemia due to a bilirubin transport defect paired with a mild ($30\%$ activity) UDPGT deficiency.

Jendrassik-Grof method

A diazo method for total and direct bilirubin measurement using caffeine-benzoate accelerator, ascorbic acid stopping reagent, and alkaline tartrate to yield a blue azodipyrrole read at $600\,nm$.

Zero-order kinetics

Enzyme reaction conditions where substrate concentration saturates all available active sites ($S > E$), making enzyme concentration the sole rate-limiting factor.

Competitive inhibitor

A substance that reversibly binds to an enzyme's active site in direct competition with the substrate, which can be overcome by increasing substrate concentration.

De Ritis ratio

The ratio of AST to ALT ($\text{AST}/\text{ALT}$); a ratio $<1$ reflects acute viral or hepatocellular injury, whereas a ratio $>3$ indicates severe necrosis such as alcoholic hepatitis.

Bowers-McComb method

The reference colorimetric method for alkaline phosphatase (ALP) measurement utilizing p-nitrophenylphosphate (PNPP) substrate at pH $9\text{--}10$ with magnesium ions.

Anion gap

A calculated mathematical parameter defined as $\text{Na}^+ - (\text{HCO}_3^- + \text{Cl}^-)$, used as a quality control check for electrolyte instruments and to evaluate metabolic acidosis.

Cotlove chloridometer

An instrument utilizing coulometric titration and amperometric end-point detection to accurately quantify chloride concentration in serum and sweat samples.

Henderson-Hasselbalch equation

The fundamental blood gas equation: $\text{pH} = 6.1 + \log\left(\frac{[\text{HCO}_3^-]}{0.03 \times \text{PCO}_2}\right)$, describing the $20:1$ normal physiological ratio between bicarbonate and carbonic acid.

Metabolic acidosis

An acid-base disorder characterized by a primary decrease in bicarbonate ($\downarrow \text{HCO}_3^-$), reduced pH ($<7.35$), and compensatory respiratory hyperventilation ($\downarrow \text{PCO}_2$).

Therapeutic index

The ratio between a drug's median toxic dose and median effective dose ($\frac{TD_{50}}{ED_{50}}$); drugs with a narrow therapeutic index require therapeutic drug monitoring.

Steady state

The pharmacokinetic state achieved after 5 to 7 half-lives when the rate of drug administration equals the rate of drug metabolism and elimination.

Mees' lines

Transverse white lines appearing across the nail beds, characteristic of chronic heavy metal toxicity, particularly arsenic poisoning.