Reference
Every clinical and professional term used across the ten modules, defined in plain language. Each entry links to the module section where the term is first introduced.
118 terms
Asking the patient to state their own identifiers — “Please tell me your full name and date of birth” — rather than inviting confirmation of a name. The only acceptable method for the formal identity check.
A substance in a collection tube that changes what happens to the blood between the draw and analysis — preventing clotting, accelerating it, preserving a single analyte, or helping separate serum or plasma during centrifugation. Using the wrong tube gives a result that looks precise but is clinically misleading.
The transfer of a small amount of additive from one tube into the next on the rubber-sleeved end of the needle. Invisible but capable of changing results — for example EDTA tracked into a chemistry tube lowers calcium and raises potassium — which is the reason the order of draw exists.
The default method of hand hygiene whenever the hands are not visibly soiled — faster and kinder to skin than washing, and as effective against the organisms that matter on a clinical ward. It is not reliable against spores such as C. difficile, where soap-and-water washing is required.
A severe, rapidly progressing allergic reaction — difficulty breathing, swelling of the face, lips, or throat, rapid pulse, severe rash, or collapse — that requires immediate emergency medical help.
Holding the vein still before and during insertion by drawing the skin taut with the non-dominant hand below the puncture site, so a mobile or rolling vein does not slide away from the needle.
The inner bend of the elbow and the preferred site for adult venepuncture. Three superficial veins lie close to the surface here — the median cubital, cephalic, and basilic — one of which is almost always suitable.
An additive that prevents collected blood from clotting so it can be analysed as whole blood or plasma — for example EDTA, sodium citrate, and heparin. Each works by a different mechanism and serves a different class of test.
An arterial blood sample used to assess oxygenation and acid-base balance. Performed only by trained staff, after a modified Allen test, usually from the radial artery, with a longer post-puncture pressure hold than a venous draw.
Accidental entry of an artery instead of a vein. Recognised by bright-red rather than dark blood, spurting or pulsing flow, and rapid tube filling; the needle is removed immediately and firm pressure applied for at least 15 minutes.
A surgically created connection between an artery and a vein, used as dialysis access — the patient’s lifeline. An arm with an AV fistula or shunt is never used for venepuncture, and damage to a fistula is a serious clinical event.
Practice that prevents micro-organisms from contaminating a clean site during a procedure — clean hands, an antiseptic-prepared site left untouched until puncture, and sterile single-use equipment.
The ethical principle of respecting the patient’s right to make informed decisions about their own care — including the right to refuse a blood draw at any time before the needle enters the skin.
The vein running on the medial (inner) side of the antecubital fossa. The third-choice vein for routine venepuncture, used only when the median cubital and cephalic are both unsuitable. The basilic lies close to the brachial artery and the median nerve, so puncture here carries a higher risk of damaging either structure and is typically more painful for the patient.
Labelling each tube at the patient’s side, immediately after collection and before leaving the area, then rechecking the labels against the request form. Pre-labelling empty tubes and labelling away from the bedside both produce specimens that look correct but cannot be trusted.
The ethical principle of acting in the patient’s best interest.
The angled, cutting tip of the needle. Held bevel-up for insertion so the needle enters the skin and vein cleanly.
A test to detect micro-organisms in the blood, collected into paired aerobic and anaerobic bottles. It demands enhanced skin antisepsis and a fixed fill order (aerobic first) because contamination causes false positives, unnecessary antibiotics, and longer hospital stays.
A micro-organism carried in blood that can cause disease if it enters another person — in phlebotomy chiefly HIV, hepatitis B, and hepatitis C. Because blood-borne pathogens do not show on a patient’s chart, standard precautions are used for every patient.
The major artery running close to the basilic vein along the medial aspect of the upper arm. Identified by pulsation under the fingertip; if punctured, blood is bright red and pulsatile and the site needs firm pressure for at least 15 minutes.
The ability to understand the information given, retain it long enough to weigh it, weigh it in the balance, and communicate a decision. A patient does not lose capacity simply by disagreeing with the clinician.
Sampling blood from a lancet skin-puncture rather than a vein — heel in infants under six months, the side of a fingertip beyond that age — for small-volume and point-of-care tests. The first drop is wiped away and drops are collected without heavy squeezing.
Spinning a collection tube at speed to separate the cells from the serum or plasma, often aided by a separator gel that settles into a barrier between the two layers.
The vein running on the lateral (thumb) side of the antecubital fossa. The second-choice vein for routine venepuncture — often harder to palpate than the median cubital and with a tendency to roll under the needle on insertion. Acceptable where the median cubital is not available.
Continuous documented accountability for a specimen at every point between collection and analysis — signatures at each transfer, tamper-evident seals, and secure storage — required for legal or employment-related testing. A gap in the chain breaks the legal weight of the result.
The sequence of links by which infection spreads — infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. Breaking any single link reduces the chance that blood collection will transmit infection.
An antiseptic used for enhanced skin preparation — typically 2% chlorhexidine gluconate in 70% isopropyl alcohol, applied for 30 seconds and allowed to dry, with no re-palpation afterwards — in blood donation and blood culture collection.
A blood-collection system in which blood flows directly from the vein into the container without exposure to air. WHO prefers closed systems because they have proven safer than open systems; the evacuated tube system is closed.
An additive in serum (red) and serum-separator tubes that promotes full clotting so the serum can be separated by centrifuge for biochemistry, immunology, and serology.
An alternative blood supply to a region — for example the ulnar artery’s supply to the hand. The modified Allen test confirms collateral circulation is adequate before the radial artery is punctured.
Ongoing learning and skill maintenance carried through a phlebotomy career — regular training, certification renewal, competency reassessment, mentoring, and reflective practice. Keeps technique current and supports the safe care of patients across the years of practice.
A reason a particular site or arm must not be used for venepuncture — for example the mastectomy side, an arm with an AV fistula or an indwelling line, or skin that is broken, scarred, or oedematous.
The small volume of air in the flexible tubing of a butterfly set between the needle and the first tube. It under-fills the first tube drawn — which is why a discard tube is taken first when a citrate tube would otherwise be first.
A small non-additive (or red-top) tube drawn first to clear the dead-space air in butterfly tubing, or to clear tissue-fluid contamination after a difficult stick, before the first analytical tube is filled.
The veins on the back of the hand — the standard second-tier site when the antecubital fossa is unavailable. The draw is more painful, the veins smaller and more prone to rolling, and a smaller-gauge needle is usually required.
The needle of the evacuated tube system: a patient end that enters the vein and a rubber-sleeved end inside the tube holder, joined by a threaded hub that screws into the holder.
Ethylenediaminetetraacetic acid — the anticoagulant in the purple/lavender tube. It binds calcium to preserve cell shape for full blood counts, haematology, and cross-match, and needs a full draw for the correct blood-to-additive ratio.
The closed blood-collection system — also called the vacuum extraction system or Vacutainer — in which a pre-evacuated tube draws a calibrated volume of blood directly from the vein through a double-ended needle. The modern default for routine multi-tube venous collection.
Clean, non-sterile single-use gloves worn for every routine draw. They protect the worker from the patient’s blood and the patient from the worker’s skin flora, but they do not replace skin antisepsis at the puncture site and are discarded if they show any visible defect.
A sample for a test that requires the patient not to have eaten or drunk anything but water for a set period beforehand. If a fasting sample is requested and the patient has eaten, the draw is not assumed to be fine — the requesting clinician is contacted and local guidance followed.
The appearance of blood in the needle hub or tubing that confirms the vein has been entered, before blood is drawn into the syringe or tube.
The additive in the grey-top tube (sodium fluoride plus potassium oxalate). It slows glycolysis so glucose readings stay accurate for several days, and is drawn last among the routine tubes.
A collection of blood under the skin, visible as swelling and discolouration around the puncture site. The most common complication of venepuncture; usually caused by the needle going through the back wall of the vein or by inadequate pressure after withdrawal.
The rise in the concentration of cells and analytes in the blood when a tourniquet is left on too long. It alters the sample, which is why the tourniquet is released within a minute or two and reapplied after a pause if needed.
The destruction of red blood cells in the collected sample. The most common cause of specimen rejection — each rejection means a repeat draw, a delay to the patient’s care, and a re-cost to the service. Caused most often by mechanical trauma during the draw, prolonged tourniquet application, or improper mixing of the sample.
Cleaning the hands by alcohol-based hand rub or by washing with soap and water. The single most effective control against healthcare-associated infection, performed at defined moments before, during, and after a draw.
An infection acquired as a result of healthcare rather than the patient’s original condition. Hand hygiene is the single most effective control against it.
A capillary puncture on the lateral or medial heel of an infant under six months. The posterior heel is avoided because the needle could reach the calcaneus and injure bone.
The anticoagulant in the green-top tube. It inactivates thrombin so the sample stays as plasma rather than clotting, used for stat plasma chemistry and some endocrine tests. More tolerant of partial fills than citrate or EDTA.
A blood-borne viral infection of the liver and an occupational risk in phlebotomy. It is the only one of the three main blood-borne pathogens with a vaccine in routine clinical use; WHO recommends hepatitis B vaccination before duties involving potential blood exposure.
A blood-borne viral infection of the liver. There is no vaccine in routine use and no recommended post-exposure prophylaxis; after exposure the management pathway is follow-up testing and referral for treatment if infection is detected.
The human immunodeficiency virus — a blood-borne pathogen and an occupational risk in phlebotomy. Post-exposure prophylaxis is most effective when started as soon as possible, preferably within 24 hours and never delayed beyond 72 hours.
The structured reporting and documentation of adverse events and near-misses — securing safety first, reporting to a supervisor, documenting thoroughly, and feeding root cause analysis — so the service can prevent recurrence.
Leakage of blood or infused fluid out of the vein into the surrounding tissue. The risk is higher at the back of the hand and in oedematous tissue than at the antecubital fossa.
The patient’s freely given agreement to a specific procedure, made with enough information to understand it. Valid consent requires capacity, information, and voluntariness; the patient may refuse at any time before the needle enters the skin.
The shallow angle — thirty degrees or less — at which the needle enters the skin in one smooth motion, with the skin held taut by the thumb below the site.
A tube that does not fill to the volume the laboratory needs — from a collapsed vein, a needle not properly in the vein, a lost-vacuum tube, or premature clotting. Under-filled additive tubes (especially citrate) are rejected because the blood-to-additive ratio is wrong.
The ethical principle of fair and equal treatment for all patients, regardless of who they are.
A measurable indicator a phlebotomy service tracks to monitor and improve quality — first-attempt success rate, specimen rejection rate, contamination rate, patient satisfaction, needlestick-injury incidents, and procedure compliance.
The laboratory request (requisition) form listing the tests ordered for a patient. The patient’s stated identifiers are checked against it before the draw, and the tube labels are rechecked against it before dispatch.
The single-use sharp used to make a capillary skin puncture, selected by depth for the patient: shallower for premature and full-term infants, deeper for children and adults.
The fitting that attaches winged-set or syringe tubing to an evacuated tube holder or a syringe.
Swelling of tissue caused by impaired lymphatic drainage — a risk of drawing blood from the arm on the side of a previous mastectomy or axillary lymph-node removal.
Surgical removal of a breast. Blood is drawn from the arm opposite the side of surgery, because lymph-node removal can cause lymphoedema and a draw on the affected arm risks both an unreliable sample and harm to the patient.
The vein crossing the centre of the antecubital fossa, joining the cephalic and basilic networks. It sits between muscles, which anchors it well, and is usually the most prominent and accessible vein at the site. The first-choice vein for routine venepuncture in adults: large, well-anchored, less likely to roll under the needle, and at the safest distance from the structures that should not be punctured.
The nerve running close to the basilic vein in the antecubital region — the nerve most likely to be contacted during a poorly sited venepuncture. Contact causes sharp, electric pain and the procedure stops immediately.
Mixing an additive tube by turning it gently top-to-bottom and back, the manufacturer-specified number of times, immediately after the draw. Inversion mixes the additive evenly; shaking the tube haemolyses the sample.
The pre-puncture check of ulnar collateral circulation before radial arterial sampling. With both arteries compressed the blanched hand should flush within 5–15 seconds once ulnar pressure is released; if it does not, that radial artery is not used.
The measure of a needle’s outside diameter. The number runs opposite to bore size: a smaller gauge number means a wider bore, a larger number a narrower bore. Too large a needle traumatises the vein; too small raises the risk of haemolysis.
A penetrating injury from a used needle or other sharp, carrying a risk of blood-borne pathogen transmission to the worker. Managed by a time-limited protocol — let the wound bleed, wash with soap and water, then report for risk assessment and post-exposure prophylaxis. No exposure is too small to report.
Damage caused by the needle contacting a nerve, signalled by sharp, electric-like pain shooting down the arm, tingling, numbness, or weakness. The patient’s report is treated as definitive — the needle is withdrawn at once and the event documented.
The ethical principle of “do no harm” — minimising the risks and discomfort of the procedure.
Fluid swelling in the tissues. Oedematous tissue alters analyte concentrations, makes a vein harder to palpate accurately, and raises the risk of infiltration, so it is an area to avoid.
The only acceptable way to recap a needle when recapping is unavoidable: the cap is laid on a flat surface and the needle slid into it using only the hand holding the device, which then secures the cap. The second hand stays away.
A blood-collection system with a transfer step that exposes blood to air and adds a moment of needle handling — for example the syringe-and-needle system, where blood is drawn into a barrel and then transferred into tubes.
The fixed sequence in which multiple tubes are drawn from a single venepuncture to prevent additive carryover between tubes: blood culture, then citrate, then serum tubes, then heparin, then EDTA, then fluoride-oxalate. Local laboratory policy takes precedence over any generic sequence.
Examining a site by touch — to locate a vein, judge its depth and resilience, and distinguish a vein from a pulsating artery, a firm tendon, or a tender nerve. Vein-finding by palpation works across every skin tone, where visual inspection alone does not.
Inviting a patient to confirm a name you state — “Are you Mrs Patel?” A patient who is hard of hearing, sedated, or distracted may agree to the wrong name, so passive identification is not acceptable for the formal check.
Confirming who the patient is using two independent identifiers — full name and date of birth at minimum, checked against the laboratory request form — before every draw. The single most important non-technical step in phlebotomy; a discrepancy stops the procedure until it is resolved.
The single-use gloves, apron, eye protection, and (where required) mask worn as a second layer between the worker and the patient’s blood. PPE catches the splashes and glove-removal contamination that hand hygiene alone cannot, but it does not replace hand hygiene.
Inflammation of a vein. A vein showing signs of phlebitis — redness, hardness, tenderness — is excluded from selection.
A healthcare worker trained to draw blood samples safely and to care for the patient through the procedure. The first person in a long diagnostic pathway: everything downstream depends on the sample being correctly drawn and correctly labelled.
The practice of drawing blood from patients — for laboratory testing, transfusion, donation, or research. The term comes from the Greek “phlebo” (vein) and “tomy” (incision). The phlebotomist sits at the start of almost every diagnostic and therapeutic pathway in modern healthcare.
The fluid fraction of blood obtained when the sample is anticoagulated (not clotted) and the cells separated by centrifugation. Unlike serum, it still contains the clotting factors.
Testing performed at the patient’s side rather than in the laboratory — for example glucose or haemoglobin from a capillary sample — giving an immediate result.
Preventive treatment given after a needlestick or splash exposure. HIV PEP is the most time-sensitive step (within 72 hours); hepatitis B is managed by a vaccination booster or immunoglobulin depending on immune status; there is no recommended PEP for hepatitis C.
An error occurring before laboratory analysis — haemolysis, clotting, mislabelling, the wrong tube, or insufficient volume — that compromises the result even though the analyser runs perfectly. Most quality failures in phlebotomy are pre-analytical and happen in the phlebotomist’s hands.
The framework inside which every draw takes place — competent staff and training, written procedures, verified patient identification, controlled specimen integrity from collection to delivery, and complete documentation. A weakness in any one component is felt by the laboratory and the patient downstream.
The artery at the wrist on the thumb side. Used for arterial sampling only — never as a venepuncture site — and the artery released in the modified Allen test.
Re-covering a used needle with its cap. Two-handed recapping is a common cause of needlestick injury and is prohibited under WHO Best Practices in Phlebotomy; where recapping is genuinely unavoidable, only the one-handed scoop technique is acceptable.
Learning from experience by reviewing difficult cases, analysing successes and challenges, seeking feedback from supervisors, and keeping a learning journal — part of continuing professional development.
A vein that moves away from the needle as it advances. Managed by anchoring the vein firmly and drawing the skin taut below the site before a quick, smooth insertion; a butterfly set can help.
A structured review of an incident — a needlestick, a mislabelled sample, an unexpected complication — that traces back from the visible failure to the contributing factors. Used in healthcare to prevent recurrence rather than to assign blame.
A needle with a sheath, retractable mechanism, or blunting trigger that activates before the needle comes near the hand a second time. Where a service provides them they are not optional, and the safety mechanism is activated immediately after needle withdrawal.
The range of activities a phlebotomist is authorised, trained, and competent to perform within their role. Working within scope means recognising one’s limitations and seeking help when a task sits outside that range.
The straw-coloured fluid left after blood has been allowed to clot and the cells removed by centrifugation. The medium analysed for most biochemistry, immunology, and serology.
A tube containing a clot activator plus a gel that forms a physical barrier between the cells and the serum after centrifugation — the red-grey “tiger” or gold tube used for most routine biochemistry.
Items that can pierce skin and so require disposal into a sharps container — used needles, lancets, used capillary tubes, blood-contacted broken glass, scalpel blades, and used safety-engineered devices even after the mechanism is activated.
A puncture-resistant, labelled container kept within arm’s reach for immediate point-of-care disposal of needles and other sharps. It is replaced before it reaches the fill line, never decanted, and never reopened.
Cleaning the puncture site with a 70% alcohol swab in a circular motion from the centre outward, then allowing it to dry completely before insertion. The cleaned area is not touched again; puncturing before the alcohol dries stings and can haemolyse the sample.
The anticoagulant in the light-blue coagulation tube. It binds calcium in a controlled 1:9 citrate-to-blood ratio so clotting can be measured later; the tube must be filled to the line or the coagulation result is invalid and the sample is rejected.
The laboratory’s refusal to run a sample that cannot give a safe result — haemolysed, clotted, under-filled, or mislabelled. Each rejection means a repeat draw, a delay to the patient’s care, and a re-cost to the service; the target rejection rate is under 2%.
The baseline safety behaviours used for every venepuncture, for every patient, every time, regardless of whether a patient is known to be infectious. They include a clean work area, hand hygiene, appropriate PPE, sterile single-use equipment, sharps-injury prevention, and safe disposal of contaminated items.
Gloves reserved for procedures where the field itself must remain sterile — for example where local protocol specifies sterile technique for blood culture collection. Distinct from the clean, non-sterile examination gloves used for routine venepuncture.
Lying flat on a couch or bed. The position used for any patient with a history of fainting, marked anxiety, frailty, or a first draw, because it prevents injury from a fall if a vasovagal episode occurs.
Fainting — a transient loss of consciousness. In phlebotomy it is usually the end of a vasovagal reaction; the patient is never left unattended and is monitored for two to three minutes before standing.
An open collection system of a hypodermic needle and a syringe, where the phlebotomist creates the vacuum manually by pulling the plunger back, then transfers the blood into tubes. Useful where evacuated tubes are unavailable or a vein is too fragile to sustain a vacuum draw.
A vein blocked or hardened by clot. A thrombosed vein lacks the resilient, springy give of a healthy vein and is unsuitable for venepuncture.
A constricting band applied four to five finger-widths above the antecubital fossa to distend the vein before venepuncture. Released before the needle is withdrawn from the vein, per WHO procedure; left on for no longer than one minute to avoid haemoconcentration and patient discomfort.
The plastic barrel — also called the evacuated tube needle holder — that holds the tube while it fills and shields the phlebotomist from the rubber-sleeved end of the needle.
A two-attempt limit on venepuncture before handing over to a more experienced colleague, commonly used in training and local-policy frameworks, rather than continuing to probe. It protects the patient from prolonged probing and the sample from pre-analytical damage.
The artery on the little-finger side of the wrist, providing collateral circulation to the hand. Not a venepuncture site; its patency is what the modified Allen test confirms before radial puncture.
The most familiar brand name for the evacuated tube collection system, often used generically for it. A closed system in which a calibrated vacuum tube draws blood directly from the vein.
A sudden drop in heart rate and blood pressure triggered by the procedure — most often by the sight of blood, the anticipation of pain, or prolonged standing. Common, frightening for the patient, and entirely manageable when recognised early.
The puncture of a vein to obtain a blood sample — the core procedure of phlebotomy. “Venepuncture” is the British spelling; “venipuncture” is the American spelling of the same procedure.
The ethical principle of truthfulness in all professional interactions — for example being honest that a needle is a brief sharp sensation rather than promising it will not hurt.
WHO’s framework naming the five points in a clinical encounter at which hand hygiene must happen: before patient contact; before a clean or aseptic procedure; after body-fluid exposure risk; after patient contact; and after contact with patient surroundings. In a venepuncture all five occur in a short window.
A short needle with two plastic wings and flexible tubing ending in a luer connector — almost universally called a butterfly. The right tool for small, fragile, rolling, hand, wrist, paediatric, or otherwise difficult draws, because the wings give a stable grip and the tubing absorbs small movements.
Join our email list and we’ll send new free guides, glossary entries, and revision tips as we publish them. No spam — unsubscribe anytime.