Phlebotomy, Hematology, and Vascular Anatomy Review

Comprehensive vocabulary flashcards covering the preanalytical testing phase, blood components, collection tube additives, order of draw, phlebotomy equipment, infection control, hemostasis, vascular anatomy, and the history of bloodletting.

Preanalytical Phase

The stage of clinical laboratory testing that occurs before sample analysis, encompassing patient preparation, specimen collection, labeling, handling, storage, and transportation.

Vasovagal Response

A stress- or needle-fear-induced physiological reaction that elevates levels of cortisol, adrenocorticotropic hormone (ACTH), catecholamines, and aldosterone, increases white blood cell count, and can induce respiratory alkalosis.

Quantity Not Sufficient (QNS)

A preanalytical laboratory specimen rejection criterion indicating that the volume of blood collected was inadequate to execute the requested assay or maintain the proper blood-to-additive ratio.

Erythrocytes (Red Blood Cells)

Small, biconcave, disk-shaped anucleated blood cells produced by bone marrow that contain hemoglobin molecules to facilitate the transport of oxygen and carbon dioxide.

Hemoglobin

A protein molecule within erythrocytes composed of four heme groups, each containing a central iron atom capable of binding oxygen to transport up to four oxygen molecules from the lungs to body tissues.

Granulocytes

A category of leukocytes containing visible cytoplasmic granules, consisting of neutrophils ($60\text{--}70\%$; phagocytosis and superoxide radical release), eosinophils ($2\text{--}4\%$; parasitic infections and allergic reactions), and basophils ($0.5\%$; release of histamine and heparin during inflammation).

Agranulocytes

A category of leukocytes lacking prominent cytoplasmic granules, consisting of monocytes ($2\text{--}10\%$; largest WBCs, amoeboid, producing cytokines to destroy pathogens) and lymphocytes ($20\text{--}40\%$; comprising antibody-producing B-cells, cell-destroying T-cells, and innate natural killer cells).

Thrombocytes (Platelets)

Cellular fragments derived from megakaryocytes that promote clot formation; they contain $\alpha$-granules (storing von Willebrand factor), dense granules (storing ATP and serotonin), and surface receptors including thrombin and glycoprotein IIb/IIIa.

Blood Plasma

The liquid matrix constituting approximately $55\%$ of total blood volume, composed of $92\%$ water, $7\%$ plasma proteins (albumin, globulins, and fibrinogen), and dissolved electrolytes, nutrients, waste products, and hormones.

Blood Serum

The clear remnant liquid obtained after whole blood has clotted, which is chemically distinct from plasma because it lacks the coagulation protein fibrinogen.

Forward Typing

A blood bank typing procedure that utilizes known commercial antibodies (anti-A and anti-B) against patient red blood cells to determine the presence of surface A and B antigens.

Reverse Typing

A blood bank typing procedure that utilizes known reagent red blood cells mixed with patient serum to identify circulating ABO antibodies.

Standard Order of Draw

The universally recommended sequence for drawing blood collection tubes (Blood cultures $\rightarrow$ Light blue $\rightarrow$ Red/Gold $\rightarrow$ Green $\rightarrow$ Lavender/Pink $\rightarrow$ Gray) to eliminate spurious lab values caused by additive cross-contamination.

Light Blue Top Tube

A blood collection tube containing $3.2\%$ sodium citrate that chelates calcium ions to temporarily block coagulation; maintains a strict 9:1 blood-to-anticoagulant ratio (filling to $\ge 90\%$ of indicated volume) for PT and aPTT testing.

Lavender Top Tube

A blood collection tube containing ethylenediaminetetraacetic acid ($\text{K}_2\text{EDTA}$ or $\text{K}_3\text{EDTA}$), a chelating anticoagulant that preserves blood cell morphology for complete blood counts (CBC), blood typing, and genetic testing.

Serum Separator Tube (SST)

A blood collection tube (gold or tiger stopper) containing a clot activator (usually silica particles) and a polymer separation gel that forms an impermeable barrier between clotted cells and serum upon centrifugation.

Green Top Tube

A blood collection tube containing lithium, sodium, or ammonium heparin, which prevents clotting by enhancing antithrombin activity to allow rapid plasma separation for routine chemistry and STAT tests.

Gray Top Tube

A blood collection tube containing an antiglycolytic agent (sodium fluoride) and potassium oxalate to inhibit glucose metabolism, used specifically for accurate blood glucose analysis.

Butterfly Needle

A winged blood collection set featuring flexible plastic wings and short tubing attached to a fine-gauge needle (commonly 22G–23G), specifically used to cannulate small, delicate, or fragile veins.

Tourniquet

A constricting band applied $3\text{--}4\text{ inches}$ above the venipuncture site for no more than $1\text{ minute}$ to distend veins for palpation while avoiding hemoconcentration and bruising.

Modes of Transmission

The pathways by which pathogens travel from a reservoir to a susceptible host, classified into airborne, contact, droplet, vector, and vehicle transmission.

Standard Precautions

An infection control framework mandating that blood, non-intact skin, mucous membranes, and all bodily fluids of every patient be treated as potentially infectious.

Hemostasis

The physiological arrest of bleeding following vascular injury, proceeding sequentially through vasoconstriction, primary platelet plug formation, secondary hemostatic plug formation, and fibrinolysis.

Vasoconstriction

The immediate reduction in blood vessel diameter triggered by contraction of smooth muscle fibers within the tunica media, serving to restrict blood flow past a vascular lesion.

Fibrinolysis

The physiological dissolution of a fibrin meshwork in which the proenzyme plasminogen is converted into active plasmin to clear vascular thrombi and dissolve clots as tissue repairs.

Coagulation Cascade

A sequential activation of plasma protein factors via the tissue factor-initiated extrinsic pathway or surface-contact intrinsic pathway, merging into a common pathway that cleaves fibrinogen into insoluble fibrin.

Tunica Media

The middle layer of a blood vessel wall composed of smooth muscle tissue and elastic fibers; it is the thickest coat in arteries and controls vessel diameter.

Antecubital Fossa

The shallow triangular depression on the anterior arm surface slightly below the elbow bend, serving as the first-choice anatomical region for venipuncture.

Median Cubital Vein

The first-choice antecubital vein in an H-shaped pattern, situated near the center of the elbow bend; preferred due to its large size, superficial path, firm anchorage, and low pain and bruising risk.

Cephalic Vein

The second-choice antecubital vein, positioned along the lateral aspect of the arm; it is well-anchored and frequently the primary palpable option in obese patients.

Basilic Vein

The last-choice antecubital vein, situated on the medial side; it rolls easily and lies adjacent to the brachial artery, median nerve, and medial cutaneous nerve branches.

Disseminated Intravascular Coagulation (DIC)

A severe secondary hematologic disorder marked by widespread systemic clotting and fibrinolysis that depletes clotting factors and platelets, resulting in uncontrollable bleeding.

Barber-Surgeons

Medieval medical practitioners organized in 1210 who were split into Surgeons of the Long Robe and Surgeons of the Short Robe; the latter were legally restricted to bloodletting, wound care, cupping, leeching, tooth extraction, and enema administration.

Barber's Pole

A traditional profession sign derived from bloodletting: the central pole represents the staff gripped by patients to engorge veins, the red stripe represents blood, the white stripe represents bandages, and the blue stripe theoretically symbolizes veins.

Cupping

An ancient bloodletting method involving the placement of a heated suction apparatus against intact or scarified skin to draw blood to the surface.

Fleams

Historical bloodletting instruments featuring wide, double-edged blades used to puncture or incise larger veins and arteries to withdraw substantial quantities of blood.