NMCB Licensure Exam key terms

How closely an average test result matches the true value for a sample, usually judged against a reference method; it reflects systematic error rather than random variation.

How closely repeated measurements of the same sample agree with each other under stated conditions; it reflects random error and is commonly expressed as standard deviation or coefficient of variation.

The standard deviation of a set of replicate results divided by their mean, usually multiplied by 100 and reported as a percentage; it allows comparison of variability across tests with different units.

The range of results expected in a defined healthy population, typically spanning the central 95 percent of values; results outside it are flagged but do not by themselves prove disease.

A result so far outside expected limits that it suggests immediate danger to the patient, requiring prompt verification and notification of the responsible clinician according to written policy.

A quality rule that compares a patient's current result with a previous one and flags unexpectedly large changes, helping detect specimen mix-ups, dilution errors, or acute clinical deterioration.

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

A graph plotting control results over time against lines marking the mean and multiples of the standard deviation, used to spot trends, shifts, and random outliers.

A set of statistical rules, such as one point beyond two standard deviations or two consecutive points beyond two standard deviations, that decide when a control run should be rejected.

A measure of how widely values spread around their mean, calculated from the differences between each value and the average; larger values indicate greater dispersion.

The smallest amount of an analyte a method can reliably distinguish from zero, often expressed as the limit of detection; it is not the same as the ability to detect disease.

The ability of a method to measure only the intended substance without interference from related compounds, metabolites, or cross-reacting antibodies present in the sample.

The range of concentrations over which a method's signal remains proportional to the amount of analyte, so results need no dilution or correction to be valid.

The process of measuring materials of known concentration to establish or verify the relationship between instrument signal and analyte amount before patient testing.

In diagnostic testing, the proportion of people who truly have a condition and are correctly identified as positive; highly sensitive tests are useful for ruling out disease.

In diagnostic testing, the proportion of people without a condition who are correctly identified as negative; highly specific tests are useful for confirming a diagnosis.

The probability that a person with a positive result actually has the condition, which depends on disease prevalence as well as on the test's sensitivity and specificity.

The probability that a person with a negative result truly does not have the condition; like its positive counterpart, it changes with the prevalence of the disease in the population tested.

Binding of an antibody or assay reagent to a substance other than its intended target, which can produce falsely elevated or falsely positive results.

Any substance or condition in a specimen, such as hemolysis, lipemia, drugs, or icterus, that alters a measured result away from the true value.

A molecule, often a protein or polysaccharide, that the immune system can recognize and that may trigger production of antibodies or a cellular response.

An immunoglobulin produced by plasma cells that binds specifically to an antigen; its structure and class determine how it participates in immune defense and laboratory reactions.

The small, specific region of an antigen that an antibody or T-cell receptor actually contacts, determining the fine specificity of the immune response.

A group of plasma proteins that activate in sequence to coat microbes, attract immune cells, and form pores that lyse target cells; it also enhances antibody-mediated clearance.

Coating of a particle or microbe with antibodies or complement fragments so that phagocytes can bind and engulf it more efficiently.

The process by which cells such as neutrophils and macrophages engulf particles, microbes, or debris into internal vesicles where they are destroyed.

A differential staining method that divides bacteria into Gram-positive and Gram-negative groups based on cell wall structure, giving rapid clues for identification and therapy.

Growth of microorganisms on or in nutrient media under controlled conditions so they can be detected, isolated, identified, and tested for antimicrobial susceptibility.

A unit used to express viable microbial counts, where each visible colony is assumed to arise from one or more living cells; reported per milliliter or per gram.

The lowest concentration of an antimicrobial agent that visibly prevents growth of a microorganism under defined test conditions, guiding selection and dosing of therapy.

A panel of hematology measurements including red cell count, hemoglobin, hematocrit, red cell indices, white cell count with differential, and platelet count.

The proportion of blood volume occupied by red cells, usually reported as a percentage; it roughly equals three times the hemoglobin concentration in grams per deciliter.

The average volume of a red blood cell, derived from hematocrit and red cell count; it classifies anemia as microcytic, normocytic, or macrocytic.

Breakdown of red blood cells with release of hemoglobin, which may occur in the patient, during collection, or in the laboratory and can distort many chemistry results.

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

Barrier items such as gloves, gowns, masks, eye protection, and face shields worn to prevent contact with infectious agents, chemicals, or other hazards.

A graded set of containment practices, equipment, and facility design requirements, from level one to four, matched to the risk of the agents being handled.

Documented, unbroken record of who collected, handled, and stored a specimen or evidence from collection through reporting, required for legal and forensic testing.

A patient's voluntary agreement to testing or research after receiving and understanding relevant information about purpose, risks, benefits, and alternatives.

The ethical and legal duty to protect patient information from unauthorized disclosure, limiting access to those who need it for care, quality, or legal purposes.

Refusal to test a sample that fails acceptance criteria such as wrong tube, insufficient volume, hemolysis, improper labeling, or delay beyond stability limits, with documentation and request for recollection.

The interval from specimen receipt or order entry to result reporting, a key performance measure used in laboratory management to assess service efficiency.