Free AMT MLT Exam Flashcards

Precision is the reproducibility of repeated measurements; accuracy is closeness to the accepted target. Results can cluster tightly yet remain inaccurate when a systematic bias shifts the whole cluster away from the target.

A shift is a sustained cluster of control values on one side of the mean, often after a discrete system change. A trend is progressive movement in one direction over time, often suggesting gradual deterioration such as reagent aging or instrument drift.

Calibration establishes how instrument response maps to known concentration or activity. Quality control then challenges that calibrated system over time to detect instability, bias, or imprecision before patient results are released.

Relative centrifugal force depends on both rotor radius and the square of RPM. Because rotor radii can differ, RPM alone does not define force; opposing loads must also be balanced by mass to protect specimens and equipment.

Plasma is separated from anticoagulated blood and retains fibrinogen and other clotting factors. Serum is the liquid remaining after clot formation, so fibrinogen has been consumed in the clot.

The analytical result belongs only to the person from whom the specimen came. Matching at least two patient-specific identifiers to the order and labeling in the patient's presence prevents a technically correct result from being assigned to the wrong patient.

Dilution factor equals total final volume divided by specimen volume. When the assay result is obtained from the diluted sample, multiply that result by the dilution factor to recover the original concentration, assuming the dilution was prepared accurately.

Absorbance increases in proportion to the concentration of the absorbing substance and the light path length. As absorbance rises, the fraction of light transmitted through the sample falls.

Conjugated bilirubin is water-soluble and can be filtered when present in plasma. Unconjugated bilirubin circulates tightly bound to albumin and is not normally filtered by the glomerulus.

Cell rupture releases intracellular constituents and hemoglobin into the specimen. Potassium, LD, and AST may rise, while free hemoglobin can also create method-dependent spectral or chemical interference; the laboratory must follow its hemolysis-index policy.

Glucose is a measurement at one moment, whereas HbA1c reflects glycation over the circulating red-cell population's recent lifespan. Altered red-cell survival, transfusion, or a hemoglobin variant can make HbA1c misleading even when the current glucose is measured correctly.

The primary change is decreased bicarbonate, which lowers pH. Ventilation increases as compensation, reducing pCO2; compensation limits the pH change but does not by itself make the underlying metabolic process disappear.

Both relate to renal handling, but BUN is strongly affected by hydration, protein intake, catabolism, and gastrointestinal bleeding. Creatinine and estimated GFR are usually more directly useful for filtration, while muscle mass and assay limitations still matter.

Alkaline phosphatase can arise from hepatobiliary or bone sources. A parallel GGT increase supports a hepatobiliary source, whereas an isolated alkaline phosphatase increase prompts consideration of bone and other sources in the clinical context.

Primary thyroid failure typically produces low free T4 with increased TSH because pituitary feedback is intact. Low free T4 with a low or inappropriately normal TSH raises concern for central hypothyroidism or another confounding condition.

Drug concentration changes across the dosing interval and during distribution. Interpreting a peak, trough, or other timed level requires the dose time, collection time, route, dosing history, and whether steady state was expected.

MCV describes average red-cell volume and classifies cells as microcytic, normocytic, or macrocytic. Hemoglobin indicates oxygen-carrying pigment concentration but does not identify the size pattern that helps organize an anemia differential.

It indicates that marrow is responding by releasing young red cells, as can occur after blood loss, hemolysis, or effective treatment. In anemia, the response should be interpreted with correction for the reduced red-cell mass and for premature reticulocyte release.

Rouleaux forms orderly coin-like stacks, commonly from increased plasma proteins, and tends to disperse with saline replacement. Agglutination forms irregular clumps from antibody-mediated binding and requires investigation of temperature and antibody effects.

It means increased immature neutrophil forms, especially bands and earlier granulocytic stages, are entering circulation. Toxic granulation, Dohle bodies, or vacuolation can add evidence of a reactive process but must be interpreted with the full blood picture.

Suspect an in-vitro artifact such as EDTA-associated clumping rather than immediately reporting true thrombocytopenia. Review the smear, follow analyzer flags, and recollect using the laboratory's approved alternate anticoagulant procedure when indicated.

Some counting systems include nucleated red cells in the nucleated-cell signal used for the WBC result. A smear or analyzer flag can reveal the interference so the WBC can be corrected or verified according to the instrument method.

PT is most sensitive to the extrinsic and common pathways, while aPTT evaluates the intrinsic and common pathways. Prolongation of both suggests a common-pathway problem, multiple factor deficiencies, or an anticoagulant effect rather than one isolated arm.

D-dimer demonstrates breakdown of cross-linked fibrin, so it shows that clot formation and fibrinolysis have occurred. It is not specific for thrombosis and can rise with inflammation, surgery, pregnancy, age, or other conditions.

Visible lattices form best near antigen-antibody equivalence. Antibody excess is the prozone effect and antigen excess is the postzone effect; changing the specimen or reagent proportion can restore lattice formation and reveal the reaction.

Nontreponemal assays detect reagin antibodies, can have biologic false positives, and provide titers useful for following response. Treponemal assays target antibodies to the organism and are more specific, but often remain reactive after successful treatment.

Forward typing tests patient red cells with anti-A and anti-B reagents to detect antigens. Reverse typing tests patient plasma against known A1 and B cells to detect expected antibodies; the two results should agree before a type is assigned.

The direct test detects IgG or complement already coating red cells in vivo. The indirect method incubates patient plasma with reagent red cells in vitro and then detects sensitization, supporting antibody screening, identification, and compatibility testing.

The screen looks for unexpected antibodies using selected reagent cells; the crossmatch evaluates compatibility between patient plasma and the actual donor unit or applies a validated electronic method. History, current testing, and laboratory policy determine the required method.

They must agglutinate to show that active anti-human globulin reagent was added and that washing removed unbound globulin. Failure of check cells to react invalidates the negative AHG result.

Select donor red cells lacking the corresponding antigen and demonstrate compatibility by the required antiglobulin method. The patient's antigen typing and prior antibody history help confirm and preserve the identification even if the antibody later weakens.

Leukoreduction removes most donor leukocytes and reduces leukocyte-related complications such as febrile reactions. Irradiation prevents viable donor T lymphocytes from proliferating, which protects susceptible recipients from transfusion-associated graft-versus-host disease.

Plasma supplies multiple coagulation factors, cryoprecipitate is a concentrated source of fibrinogen and selected proteins, and platelets provide primary-hemostasis cellular support. Component choice follows the documented deficiency and clinical setting.

Stop the transfusion and keep the IV line open with 0.9% sodium chloride through new tubing under the clinical protocol. Verify patient and unit identification, notify the transfusion service, and begin the workup with clerical recheck and inspection followed by directed testing such as DAT and hemolysis evaluation.

A selective medium suppresses some organisms while permitting others to grow. A differential medium contains indicators that reveal metabolic or biochemical differences among organisms that grow; one medium can perform both roles.

Catalase separates staphylococci and related catalase-positive cocci from streptococci and enterococci. Among staphylococci, a positive coagulase reaction supports identification of Staphylococcus aureus in the appropriate morphology and test system.

Bile salts and crystal violet select for many gram-negative bacilli by inhibiting much gram-positive growth. A pH indicator then differentiates lactose fermenters, which produce colored colonies, from nonfermenters.

Growth occurs throughout the tube because the organism can grow without oxygen, but it is heaviest near the oxygen-rich top because aerobic respiration yields more energy. This differs from growth restricted to the top or bottom.

Decolorizer should remove the crystal-violet iodine complex from gram-negative cells while gram-positive cells retain it in thick peptidoglycan. Too much causes false gram-negative staining; too little can leave gram-negative cells falsely purple.

A lipid-rich, mycolic-acid cell wall retains the primary carbol-fuchsin stain despite acid-alcohol decolorization. Non-acid-fast material loses the primary stain and takes the counterstain.

MIC is the lowest antimicrobial concentration that prevents visible growth under standardized conditions. Disk diffusion produces a zone diameter; each result must be interpreted with organism- and drug-specific breakpoints rather than by comparing raw numbers across drugs.

KOH clears keratin and cellular debris that can obscure fungal elements while leaving many fungal walls visible. The preparation can rapidly show yeast or hyphal forms but does not replace culture or other identification methods when required.

Specific gravity reflects the density contributed by both the number and mass of dissolved particles, so large molecules can disproportionately affect it. Osmolality reflects the number of dissolved particles per mass of solvent and better represents concentrating ability.

It detects heme peroxidase activity, so intact RBCs, free hemoglobin, and myoglobin can all produce a reaction. Microscopy and the clinical context help distinguish hematuria from hemoglobinuria or myoglobinuria.

Complete biliary obstruction can produce urine conjugated bilirubin with low or absent urobilinogen. Increased red-cell breakdown can increase urobilinogen without urine bilirubin because the excess circulating bilirubin is initially unconjugated.

The routine strip pad is most sensitive to albumin. Sulfosalicylic acid precipitates a broader range of proteins, so discordant SSA positivity can suggest non-albumin proteins, although turbidity and interfering substances still require control.

Casts form in renal tubules from uromodulin matrix under conditions favoring gel formation. Cells trapped in that matrix therefore point to an intrarenal process; RBC casts suggest glomerular bleeding, while WBC casts support renal inflammation or infection.

Cystine forms colorless hexagonal plates, usually in acidic urine. Its presence is abnormal and supports cystinuria, so it should not be dismissed as a common incidental crystal.

A traumatic collection can cause RBC counts to fall in later tubes, but clearing can also occur when a traumatic tap accompanies a true hemorrhage. Interpret the final-tube count with xanthochromia, collection timing and method, imaging, and the clinical context rather than using tube-to-tube clearing alone.

A transudate results from systemic hydrostatic or oncotic imbalance and is relatively low in protein and cells. An exudate reflects local inflammation, infection, or tissue injury and has greater protein and cellular content; paired fluid and serum measurements aid classification.