Medical Laboratory Scientist key terms

A test that mixes a patient's serum with reagent red cells to detect unexpected antibodies against red cell antigens before transfusion or pregnancy. A positive result requires identification of the antibody.

A set of reagent red cells with known antigen profiles used to determine the specificity of an antibody detected in serum. Reaction patterns across the panel reveal which antigen the antibody targets.

A test that detects antibodies or complement bound to a patient's own red cells in vivo using anti-human globulin reagent. It is central to diagnosing autoimmune hemolysis and hemolytic transfusion reactions.

A technique that removes antibodies bound to red cells so they can be tested against panel cells. It is used to characterize antibodies in positive direct antiglobulin tests, such as in hemolytic disease of the newborn.

The compatibility test mixing donor red cells with recipient serum before transfusion. It confirms the donor unit lacks antigens corresponding to antibodies in the recipient and verifies ABO compatibility.

Determination of a person's ABO blood type by testing red cells with anti-A and anti-B reagents (forward typing) and serum with A and B cells (reverse typing). Discrepancies require investigation.

Testing of red cells for the D antigen to classify a person as Rh positive or Rh negative. Rh-negative recipients must receive Rh-negative red cells to prevent anti-D immunization.

The range of results expected in a healthy population, typically spanning the central 95 percent of values. Results are interpreted against it, and each laboratory establishes or verifies its own intervals.

The smallest concentration of an analyte that a method can reliably detect, often expressed as the limit of detection. It differs from clinical sensitivity, which concerns detection of disease.

The ability of an assay to produce results proportional to analyte concentration across a stated range. Linearity studies verify that diluted or concentrated specimens recover expected values.

A rule that compares a patient's current result with a previous result and flags differences exceeding a defined threshold. It helps detect specimen mix-ups, mislabeling, and acute clinical changes.

A clotting test that measures the extrinsic and common pathways by adding tissue factor and calcium to citrated plasma. It is used to monitor warfarin therapy and assess liver synthetic function.

A clotting test that assesses the intrinsic and common pathways using a contact activator and phospholipid. It monitors unfractionated heparin therapy and screens for factor deficiencies.

A standardized ratio calculated from the prothrombin time using the thromboplastin's international sensitivity index. It allows comparison of warfarin effect across laboratories and reagent lots.

A degradation product of cross-linked fibrin released when clots are broken down by plasmin. Elevated levels support a diagnosis of thrombosis, while normal levels help exclude it.

A soluble plasma protein converted to insoluble fibrin by thrombin during clot formation. Its measurement using the Clauss method assesses bleeding risk and disseminated intravascular coagulation.

A panel measuring red cell count, hemoglobin, hematocrit, and indices, plus white cell and platelet counts with differential. It is the most frequently ordered hematology test.

The average volume of a red cell, derived from hematocrit divided by red cell count. It classifies anemia as microcytic, normocytic, or macrocytic and guides further testing.

The percentage or absolute number of immature red cells in blood, reflecting bone marrow response. An elevated count indicates hemolysis or blood loss; a low count suggests marrow failure.

A stained drop of blood examined microscopically to assess cell morphology, distribution, and manual differential. It confirms automated analyzer findings and reveals abnormalities like blasts or schistocytes.

A technique that passes cells through a laser beam to measure size, granularity, and surface markers labeled with fluorescent antibodies. It is used for immunophenotyping leukemias and lymphocyte subsets.

A method using enzyme-labeled antibodies or antigens to detect and quantify analytes, with signal generated by substrate conversion. Variants include sandwich and competitive formats used in serology and hormone testing.

A technique that separates proteins by electrophoresis, transfers them to a membrane, and detects specific proteins with labeled antibodies. It is used as a confirmatory test for antibodies to specific antigens.

The set of procedures that monitor assay performance by testing materials with known values alongside patient samples. Results are plotted on charts and evaluated against acceptance rules before reporting.

A control chart plotting quality control results over time with mean and standard deviation limits. It visually reveals shifts, trends, and random error in an analytical process.

A set of statistical rules that interpret quality control data to decide whether to accept or reject a run. Rules such as 1-3s and 2-2s balance error detection against false rejection.

External evaluation in which a laboratory tests blinded specimens and compares results with peer laboratories. It is required for accreditation and identifies systematic performance problems.

The lowest antimicrobial concentration that inhibits visible growth of a bacterial isolate under standardized conditions. It guides drug selection and dosing and is compared with susceptibility breakpoints.

A susceptibility method in which antibiotic-impregnated disks are placed on an inoculated agar plate and zone diameters are measured. Zones are interpreted against standardized tables to classify isolates.

A concentration or zone diameter threshold used to categorize an organism as susceptible, intermediate, or resistant to an antimicrobial. Breakpoints are established by standards organizations and updated periodically.

A mass spectrometry method that identifies microorganisms by comparing their protein spectral patterns with a reference library. It provides rapid, accurate species-level identification from colonies.

A technique that amplifies a specific DNA sequence through repeated cycles of denaturation, primer annealing, and extension. It enables detection and quantification of pathogens and genetic variants.

A polymerase chain reaction that measures product accumulation during each cycle using fluorescent reporters. It allows quantification of target nucleic acid and faster turnaround than endpoint detection.

The PCR cycle at which fluorescence first exceeds a defined threshold. Lower values indicate higher target concentration, though quantification requires a standard curve or reference.

The standardized sequence for filling blood collection tubes that prevents additive carryover between tubes. It generally places blood culture and coagulation tubes before tubes containing clot activators or other additives.

Rupture of red blood cells that releases hemoglobin into serum or plasma, reddening the specimen and interfering with many assays. In vitro hemolysis often results from improper collection or handling.

A method applied to blood components that inactivates or removes infectious agents while preserving component function. Examples include photochemical treatment and solvent-detergent processing of plasma.

Software that manages specimen accessioning, result entry, reporting, and billing within a laboratory. It interfaces with analyzers and electronic health records to support workflow and data integrity.