Egyptian Board Clinical Pathology key terms

The range of test results expected in a healthy reference population, usually spanning the central 95% of values, used to judge whether a patient result is normal or abnormal.

The random scatter of repeated measurements of the same sample around its mean, usually expressed as a coefficient of variation and monitored through internal quality control.

A rule that compares a patient's current result with a previous result from the same person and flags unexpectedly large changes for review before reporting.

The difference between measured cations and anions, calculated as sodium minus chloride plus bicarbonate, used to classify metabolic acidosis by the presence of unmeasured anions.

The difference between measured osmolality and calculated osmolality, indicating the presence of unmeasured osmotically active substances such as ethanol, methanol or ethylene glycol.

A cardiac muscle protein released into blood when myocytes are damaged; a rise and fall pattern with at least one value above the 99th percentile upper reference limit supports acute myocardial infarction.

A panel reporting haemoglobin, red cell indices, white cell count with subtypes, and platelet count; the starting point for evaluating anaemia, infection and haematological malignancy.

The percentage or absolute number of young red cells containing residual RNA, reflecting marrow red cell production and helping classify anaemia as hypoproliferative or hyperproliferative.

A stained blood smear examined microscopically to assess cell morphology, red cell shape and size, white cell maturation and platelet adequacy, confirming or refuting automated analyser findings.

A group of tests including prothrombin time and activated partial thromboplastin time that assess the extrinsic and intrinsic clotting pathways and detect factor deficiency or inhibitor effects.

A test in which patient plasma is mixed with normal plasma to determine whether a prolonged clotting time corrects, suggesting factor deficiency, or fails to correct, suggesting an inhibitor such as lupus anticoagulant.

Pre-transfusion testing that identifies a person's red cell ABO antigens and RhD status and the corresponding plasma antibodies, forming the basis for selecting compatible blood components.

A test of patient serum against reagent red cells to detect clinically significant unexpected antibodies against red cell antigens before transfusion or during pregnancy.

The final compatibility test between donor red cells and recipient serum, performed to prevent haemolytic transfusion reactions after ABO grouping and antibody screening.

A differential staining method that divides bacteria into Gram-positive and Gram-negative groups by cell wall structure, giving a rapid preliminary clue from clinical specimens before culture results.

The process of growing an organism from a specimen and testing its susceptibility to antimicrobial agents to guide appropriate therapy.

The lowest concentration of an antimicrobial that prevents visible growth of a bacterium in vitro; interpreted against clinical breakpoints to classify the isolate as susceptible, intermediate or resistant.

A microbiological test in which blood is inoculated into culture media to detect bacteraemia or fungaemia, with collection technique and timing strongly influencing sensitivity.

The interval after infection when a pathogen is present but specific antibodies are not yet detectable, so antibody-only testing may give a false-negative result.

An immunoassay using enzyme-labelled antibodies or antigens that produce a colour signal proportional to the target, widely used for screening antibodies and antigens in infectious disease serology.

A molecular technique that amplifies specific pathogen DNA or RNA to detect infection directly, often earlier than serology and with high sensitivity and specificity.

A screening immunofluorescence or immunoassay test for autoantibodies against nuclear components, used in the investigation of systemic lupus erythematosus and other connective tissue diseases.

An autoantibody directed against native double-stranded DNA, relatively specific for systemic lupus erythematosus and associated with disease activity and lupus nephritis.

Serum proteins of the complement cascade; low levels suggest consumption by immune complexes and are used to monitor activity in lupus and other immune-complex diseases.

A technique that passes single cells through a laser beam and measures surface or intracellular markers, widely used for immunophenotyping leukaemias and lymphomas and for lymphocyte subset counts.

A method using labelled antibodies to detect specific antigens in tissue sections, allowing precise classification and origin assignment of tumours on formalin-fixed paraffin-embedded material.

The standard chemical preservation of tissue in buffered formalin, which cross-links proteins to maintain structure but can alter antigenicity and nucleic acid quality if delayed or prolonged.

Rapid intraoperative tissue preparation by freezing and sectioning, used to give a provisional diagnosis during surgery, for example to confirm margin clearance or tumour type.

A minimally invasive sampling technique using a thin needle to obtain cells for cytological examination, often used for thyroid, breast and lymph node lesions.

A standardised reporting framework that assigns cytological or histological findings to defined diagnostic categories with implied risk of malignancy and recommended management.

An in vitro method that repeatedly copies a target DNA sequence using primers and thermostable polymerase, enabling detection of very small amounts of specific genetic material.

A chain-termination DNA sequencing method that reads one fragment at a time, still the reference standard for confirming single-gene variants detected by other methods.

A genetic change whose link to disease is not established; it should not be used alone to make clinical decisions and may be reclassified as evidence accumulates.

Microscopic analysis of condensed chromosomes arranged by size and banding pattern to detect numerical and large structural chromosomal abnormalities.

A technique using fluorescent DNA probes that bind specific chromosomal regions, allowing detection of deletions, amplifications and translocations in interphase or metaphase cells.

Daily testing of control materials with known values alongside patient samples to verify that a method performs within predefined limits before results are released.

A programme in which an outside body sends unknown samples and compares a laboratory's results with those of peer laboratories, providing objective evidence of analytical performance.

A quality metric expressing process performance in defects per million opportunities, used to set quality control rules and to judge whether a method meets required precision and bias goals.

A documented process for promptly informing the responsible clinician of results that may be life-threatening, with recording of the notification to close the communication loop.

A ventilated enclosure that protects the operator, the sample and the environment from aerosols generated during handling of infectious material; class II cabinets are standard in clinical laboratories.

Infection control practices applied to all patients regardless of diagnosis, including hand hygiene, gloves, gowns and safe handling of sharps and body fluids.

A percutaneous exposure to a needle or other sharp object that may transmit bloodborne pathogens, requiring immediate first aid, source assessment and post-exposure prophylaxis decisions.

A patient's voluntary agreement to a test or procedure after receiving understandable information about its purpose, risks, alternatives and consequences, documented before the event.

The ethical and legal duty to protect patient health information from unauthorised disclosure, permitting sharing only with those involved in care or as required by law.

The interval from specimen receipt or test order to result reporting, a key performance indicator used to manage clinical services and meet agreed service levels.