Introduction to Clinical Biochemistry

Comprehensive vocabulary flashcards covering the fundamentals of Clinical Biochemistry, including diagnostic terms, laboratory errors, blood components, coagulation pathways, and specimen collection protocols.

Clinical Biochemistry

Also known as clinical chemistry or chemical pathology, it is the branch of laboratory medicine in which chemical and biochemical methods are applied to the study of disease.

Diagnosis

The use of biochemical investigations to determine the presence or nature of a disease.

Prognosis

The use of biochemical investigations for the follow-up of treatment or recovery from an illness.

Hyperparathyroidism

A condition characterized in clinical biochemistry by unexpectedly raised plasma calcium levels.

Hypothyroidism

A condition characterized by raised plasma TSH and/or a low $T4$ level.

Diabetes mellitus

A condition where biochemical investigations show high random plasma glucose.

Core biochemical tests

Commonly requested tests provided by most laboratories, including sodium, potassium, chloride, bicarbonate, urea, creatinine, calcium, phosphate, total protein, albumin, bilirubin, ALP, ALT, AST, glucose, and amylase.

Specialized tests

Less commonly requested tests often performed in reference centres, including hormones, specific proteins, trace elements, vitamins, drugs, lipids, lipoproteins, and DNA analyses.

Reference values

Values obtained from individuals in good health after suitable standardization and statistical analysis under definite laboratory conditions.

Normal (Reference) Range

The values within which $95\%$ of normal healthy persons fall, set as mean reference value $\pm$ N times standard deviation.

Timing error

A laboratory error where blood is sampled at the wrong time, such as too early after drug administration for therapeutic monitoring or ignoring circadian rhythms for cortisol.

Sample collection tube error

An error occurring when the incorrect tube is used, such as using lithium-heparin tubes for lithium level measurements or EDTA tubes for calcium measurements.

Primary hemostasis

The first stage of arresting blood loss, characterized by vasoconstriction and platelet aggregation at the site of injury.

Secondary hemostasis

The process by which a blood clot is formed through coagulation.

Tissue factor

A protein expressed by cells external to blood vessels that stimulates the extrinsic pathway of coagulation.

Intrinsic pathway

The coagulation pathway activated by injury within a blood vessel, starting with the activation of factor XII (Hageman factor).

Prothrombin time (PT)

A coagulation test performed to measure the time it takes for a firm fibrin clot to form; used to monitor oral anticoagulation medication.

International Normalized Ratio (INR)

A standardized calculation where the patient's PT results are compared to the normal patient average.

Serum

The supernatant fluid collected after centrifuging clotted blood; it lacks fibrinogen and clotting factors.

Plasma

The acellular component of blood ($55\%$ of whole blood) obtained by centrifuging blood collected with an anticoagulant; it contains all clotting factors.

Sodium citrate

The additive in light-blue top tubes that prevents clotting by binding calcium; used for coagulation tests.

Sodium fluoride

The additive in gray top tubes used to inhibit glycolysis, specifically for glucose testing.

Potassium EDTA

An additive used in lavender or pink top tubes that prevents clotting by binding calcium; commonly used for hematology.