ASCP MLT key terms

Classification of red cells by A and B carbohydrate antigens on their surface, with corresponding anti-A or anti-B antibodies in plasma that can cause immediate intravascular hemolysis if incompatible blood is transfused.

Highly immunogenic protein antigen on red blood cells; a person who lacks it (D-negative) can form anti-D after exposure, causing hemolytic transfusion reactions or hemolytic disease of the newborn.

Anti-D antibody product given to D-negative mothers to prevent immunization by fetal D-positive red cells, protecting a future pregnancy from hemolytic disease of the newborn.

Test using anti-human globulin reagent to detect antibody or complement already attached to a patient's circulating red cells; helps identify autoimmune hemolysis, drug-induced hemolysis, and delayed transfusion reactions.

Testing patient serum against group O reagent red cells to detect unexpected antibodies before transfusion or pregnancy; positive results require identification of the antibody's specificity.

Procedure mixing recipient serum with donor red cells to confirm serologic compatibility before transfusion and to detect clinically significant antibodies that could destroy the transfused cells.

Nitrogenous waste produced at a fairly constant rate by muscle and removed mainly by glomerular filtration; serum concentration rises as kidney function falls.

Calculated estimate of the volume of plasma filtered by the kidneys per minute, derived from serum creatinine with age and sex; used to stage chronic kidney disease.

Difference between measured sodium and the sum of chloride and bicarbonate; a widened gap points to unmeasured anions such as ketoacids, lactate, or salicylate.

Heart muscle protein released into blood when myocardial cells are injured; serial measurements with clinical findings are used to diagnose acute myocardial infarction.

Glycated hemoglobin fraction that reflects average blood glucose over roughly the previous two to three months; used for diabetes diagnosis and long-term monitoring.

Range containing the central 95 percent of results from a healthy reference population, used as a guide for deciding whether a patient result is typical.

Panel reporting red cell count, hemoglobin, hematocrit, red cell indices, white cell count with differential, and platelet count; the standard hematology screening test.

Average volume of circulating red cells, calculated from hematocrit and red cell count, used to classify anemia as microcytic, normocytic, or macrocytic.

Percentage or absolute number of newly released young red cells in blood; the result indicates whether bone marrow is responding appropriately to anemia or blood loss.

Microscopic examination of a stained blood film to assess cell morphology, verify counts, and look for abnormalities such as blasts, schistocytes, or rouleaux that analyzers may miss.

Standardized prothrombin time ratio that corrects for differences in thromboplastin reagents; used to monitor warfarin therapy and assess coagulation factor deficiency.

Fibrin degradation product that increases when clot formation and breakdown occur; a negative result helps exclude venous thromboembolism in low-risk patients.

Differential stain that separates bacteria into gram-positive (purple) and gram-negative (pink) groups according to cell wall structure, giving rapid preliminary information from specimens and colonies.

Lowest antimicrobial concentration that visibly inhibits growth of a bacterial isolate under defined conditions; used to categorize the organism as susceptible, intermediate, or resistant.

Culture media containing inhibitors that suppress unwanted organisms plus indicators that reveal biochemical traits, such as MacConkey agar for gram-negative lactose fermenters.

Test for the enzyme that converts fibrinogen to fibrin; a positive result separates Staphylococcus aureus from most other staphylococci.

Paired aerobic and anaerobic bottles filled from one venipuncture; proper skin antisepsis is essential to avoid mistaking skin flora contaminants for true bacteremia.

Visible features of a microbial colony on solid media, including size, shape, color, hemolysis, and consistency, used with staining and biochemical tests to guide identification.

Assay in which an enzyme-labeled antigen or antibody generates a color signal proportional to target amount; common formats are direct, indirect, sandwich, and competitive.

Proportion of people who truly have a condition and test positive for it; high sensitivity means few false negatives, which suits screening.

Proportion of people without a condition who test negative; high specificity means few false positives, which suits confirmatory testing.

Assay that separates proteins by size on a membrane and then detects specific antibodies bound to them; used as a supplemental confirmation of positive screening results.

Immunofluorescence or enzyme immunoassay screen for antibodies to nuclear antigens; a positive result supports but does not by itself diagnose systemic lupus erythematosus.

Ratio of urine density to water density, reflecting solute concentration; it helps interpret concentration-dependent dipstick results and shows the kidney's ability to concentrate urine.

Semiquantitative chemical screening of urine for glucose, protein, blood, leukocyte esterase, nitrite, ketones, bilirubin, urobilinogen, and pH, with strict timing and storage requirements.

Examination of centrifuged urine sediment for red cells, white cells, epithelial cells, casts, crystals, and organisms, interpreted alongside dipstick and physical findings.

Cylinder made of Tamm-Horsfall protein formed in renal tubules; a few are normal, while increased numbers suggest proteinuria, dehydration, or tubular injury.

Ratio measured on a random urine sample that estimates daily protein excretion while correcting for urine concentration, often replacing a 24-hour collection.

Testing materials with known target values alongside patient samples to confirm a method is performing acceptably before patient results are released.

Graph of QC values over time with lines marking the mean and standard deviations, making shifts, trends, and random outliers easy to spot.

Multirule scheme that compares QC values with statistical limits to decide whether an analytical run should be accepted or rejected.

External program that sends unknown specimens to a laboratory and compares its results with peer laboratories and the expected value; required for accreditation.

Structured team investigation that traces an error or adverse event back to underlying process failures so corrective actions address the real cause.

Time from specimen receipt or order entry to result reporting; a key service measure that laboratories monitor and try to shorten.