MLT Registration key terms

A test that uses the patient's serum against known A and B reagent red cells to detect the expected reciprocal antibodies, confirming the forward ABO grouping and revealing discrepancies such as missing antibodies or unexpected ones.

A test that mixes the patient's red cells with anti-A and anti-B reagents to detect A and B antigens directly on the cell surface, establishing the cell type in ABO typing.

A test of patient serum against group O screening cells of known antigen profile, usually by indirect antiglobulin technique, to detect clinically significant unexpected red cell antibodies before transfusion or pregnancy.

A panel study using reagent red cells of varied antigen phenotypes to determine the specificity of an unexpected red cell antibody, typically following a positive antibody screen.

A test using anti-human globulin reagent to detect immunoglobulin or complement bound to the patient's red cells in vivo, used to investigate hemolytic transfusion reactions, autoimmune hemolysis, and hemolytic disease of the newborn.

A technique in which serum is incubated with red cells, then washed and exposed to anti-human globulin reagent to detect antibody that has bound to the cells in vitro, forming the basis of antibody screening and crossmatching.

The compatibility test between donor red cells and recipient serum performed before transfusion, either as a full serologic test with incubation and antiglobulin phase or as an immediate-spin or computer crossmatch when criteria are met.

A pretransfusion protocol that determines ABO and Rh type and performs an antibody screen without a full crossmatch, allowing compatible units to be located and released efficiently when transfusion becomes likely.

A solution containing antibody removed from sensitized red cells, usually by heat, acid, or other dissociation methods, then tested against panel cells to identify the antibody causing a positive direct antiglobulin test.

Testing for the D antigen on red cells with anti-D reagent, including weak D investigation when the initial result is negative or ambiguous, to determine whether Rh immune globulin or Rh-negative blood is indicated.

An antibody preparation given to Rh-negative individuals, chiefly during pregnancy or after delivery of an Rh-positive infant, to prevent alloimmunization against the D antigen and subsequent hemolytic disease of the newborn.

Fetal and neonatal anemia and jaundice caused by maternal immunoglobulin G antibodies crossing the placenta and destroying fetal red cells, most often anti-D but also other antibodies such as anti-K or anti-c.

An adverse event during or after transfusion, ranging from febrile and allergic reactions to acute hemolysis, transfusion-related acute lung injury, and sepsis, each requiring specific investigation and reporting.

The range of test results expected in a defined healthy population, usually spanning the central 95 percent of values, against which a patient result is judged as normal or abnormal.

A quality rule that compares a patient's current result with a previous result for the same analyte and flags the specimen when the change exceeds a defined threshold, suggesting error or a true clinical change.

A substance or condition in the specimen, such as hemolysis, lipemia, icterus, or a drug, that alters the measured signal and produces a result different from the true concentration.

An electrochemical sensor that measures the activity of a specific ion such as sodium, potassium, chloride, or calcium in a sample by detecting the potential generated across a selective membrane.

The calculated difference between measured cations and anions, commonly sodium minus chloride and bicarbonate, used to classify metabolic acidosis and detect unmeasured anions such as lactate or ketones.

An assay that uses a specific enzyme to convert the analyte into a measurable product, offering high specificity; common examples include glucose oxidase, urease, and creatininase procedures.

A clotting test that measures the time for citrated plasma to clot after adding tissue factor and calcium, assessing the extrinsic and common pathways and reported as seconds, ratio, or INR.

A clotting test using a contact activator and phospholipid with calcium to assess the intrinsic and common pathways, used to screen for factor deficiencies and to monitor unfractionated heparin therapy.

A standardized expression of prothrombin time calculated by raising the prothrombin time ratio to the power of the thromboplastin's international sensitivity index, allowing comparison across reagent lots and laboratories.

Anticoagulation with a vitamin K antagonist that reduces functional activity of factors II, VII, IX, and X, monitored with the international normalized ratio and reversed with vitamin K or factor concentrates.

Laboratory assessment of heparin effect, typically by activated partial thromboplastin time for unfractionated heparin or by anti-Xa assay, with results compared against a therapeutic range.

A platelet granule protein that, when bound by heparin, can trigger antibody formation and cause heparin-induced thrombocytopenia, a prothrombotic disorder detected by immunoassay and functional testing.

Fragments released when plasmin breaks down fibrin or fibrinogen, measured to support the diagnosis of disseminated intravascular coagulation and other states of accelerated fibrinolysis.

A fragment produced when cross-linked fibrin is degraded by plasmin, elevated in thrombosis and disseminated intravascular coagulation and used mainly to exclude venous thromboembolism in low-risk patients.

A consumptive coagulopathy with widespread activation of coagulation, causing depleted platelets and factors, prolonged clotting times, low fibrinogen, and elevated D-dimer, often triggered by sepsis or obstetric complications.

A panel reporting red cell count, hemoglobin, hematocrit, red cell indices, white cell count with differential, and platelet count, forming the core hematologic assessment of blood disorders.

The average volume of a red cell, calculated from hematocrit and red cell count or measured directly, used to classify anemia as microcytic, normocytic, or macrocytic.

The percentage or absolute number of immature red cells containing residual RNA, reflecting bone marrow response and helping distinguish decreased production from increased destruction in anemia.

The number of platelets per volume of blood, measured by impedance or optical methods, with low values prompting review of the smear for clumping and pseudothrombocytopenia.

A stained film of blood examined microscopically to assess red cell morphology, white cell differential, platelet adequacy, and the presence of abnormal cells or inclusions.

A screening immunofluorescence or solid-phase assay for antibodies against nuclear antigens, used to support the diagnosis of systemic lupus erythematosus and other connective tissue diseases.

A method that uses an enzyme-labeled antibody or antigen to produce a measurable color or signal proportional to analyte concentration, widely applied to infectious disease and hormone testing.

A group of serum proteins that amplify immune responses through opsonization, lysis, and inflammation, measured as C3 and C4 to assess activation in immune complex and other diseases.

A technique that separates proteins by gel electrophoresis, transfers them to a membrane, and detects specific antibodies or antigens, historically used to confirm human immunodeficiency virus infection.

The lowest concentration of an antimicrobial agent that prevents visible growth of a bacterial isolate under defined conditions, guiding susceptibility interpretation and dosing decisions.

A susceptibility method in which antibiotic-impregnated disks are placed on an inoculated agar plate and zone diameters are measured and interpreted against published breakpoints.

Laboratory procedures that determine whether a bacterial isolate is inhibited by specific antimicrobial agents, providing results that guide selection and dosing of therapy.

A culture of blood drawn into media bottles and incubated to detect bacteremia or fungemia, with collection volume and skin antisepsis being major determinants of sensitivity and contamination rate.

A quantitative measure of viable organisms in a specimen, expressed as colony-forming units per milliliter, used to judge significance in urine and other cultures.

The sequence in which blood collection tubes are filled to prevent additive carryover between tubes, generally beginning with sterile culture and coagulation tubes before serum and additive tubes.

Collection of blood by needle puncture of a vein, requiring correct patient identification, site selection, antisepsis, and technique to obtain an adequate, uncontaminated specimen.

Rupture of red cells that releases hemoglobin into the specimen, causing falsely elevated potassium, lactate dehydrogenase, and aspartate aminotransferase and interfering with many photometric assays.

Collection of blood from a finger or heel stick into small tubes or devices, used when venous access is difficult or specimen volume must be limited, with warming and avoiding squeezing to improve quality.

The set of procedures, including analysis of control materials with known values, used to verify that a test system performs within acceptable limits before patient results are reported.

External assessment in which a laboratory analyzes unknown specimens supplied by a provider and its results are compared with peer laboratories, satisfying regulatory requirements for competency.

A result so far outside normal limits that it may be life-threatening, requiring immediate notification of the responsible caregiver and documentation of the communication.