Arab Board Clinical Pathology Part 1 flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Coagulative necrosis

Necrosis in which tissue architecture is preserved for a time, typical of ischemic injury to heart, kidney, and spleen, with denaturation of structural proteins dominating.

Granuloma

A focal collection of activated macrophages (epithelioid histiocytes), often with Langhans giant cells and lymphocytes, seen in tuberculosis, sarcoidosis, and foreign-body reactions.

Anion gap

Calculated as sodium minus the sum of chloride and bicarbonate; normally about 8-12 mmol/L, and elevated when unmeasured anions such as lactate or ketones accumulate.

Winter formula

For metabolic acidosis, expected pCO2 equals 1.5 times bicarbonate plus 8, with a range of plus or minus 2; deviation indicates a mixed acid-base disorder.

Corrected calcium

Measured calcium plus 0.8 times the difference between 4.0 and the serum albumin in g/dL; used to adjust total calcium for albumin binding.

Friedewald LDL formula

LDL cholesterol equals total cholesterol minus HDL cholesterol minus triglycerides divided by 5, valid only when triglycerides are below 400 mg/dL.

MCV formula

Mean corpuscular volume equals hematocrit multiplied by 10 and divided by red cell count, expressed in femtoliters; used to classify anemia as microcytic, normocytic, or macrocytic.

Iron deficiency profile

Low serum ferritin, low serum iron, high total iron-binding capacity, low transferrin saturation, and high red cell distribution width, producing a microcytic hypochromic anemia.

DIC laboratory pattern

Prolonged PT and aPTT, low fibrinogen, elevated D-dimer and fibrin degradation products, thrombocytopenia, and schistocytes on the peripheral smear.

APL translocation

Acute promyelocytic leukemia is characterized by t(15;17) forming the PML-RARA fusion; it is treated with all-trans retinoic acid and carries a risk of disseminated intravascular coagulation.

Hepatitis B serology

HBsAg indicates current infection, anti-HBs indicates immunity, anti-HBc IgM indicates acute or recent infection, and HBeAg indicates high infectivity.

Syphilis serology strategy

Nontreponemal tests such as RPR and VDRL are used for screening and monitoring activity, while treponemal tests such as TPPA and FTA-ABS confirm the diagnosis.

MRSA detection

Methicillin resistance in Staphylococcus aureus is detected by cefoxitin or oxacillin disk testing or by identifying mecA or PBP2a, indicating resistance to most beta-lactams.

Type IV hypersensitivity

T-cell mediated delayed hypersensitivity, exemplified by tuberculin skin testing and allergic contact dermatitis, with reactions read at 48 to 72 hours.

Anti-dsDNA antibody

An antibody highly specific for systemic lupus erythematosus whose titer correlates with disease activity and risk of lupus nephritis.

Anti-CCP antibody

An antibody highly specific for rheumatoid arthritis that may appear years before clinical disease and is associated with more erosive joint disease.

Bruton agammaglobulinemia

An X-linked primary immunodeficiency with absent B cells and markedly low all immunoglobulin classes, causing recurrent bacterial infections in male infants after maternal antibody wanes.

PCR cycle steps

Each cycle consists of denaturation near 94-95 C, primer annealing near 50-65 C, and extension near 72 C, doubling the target sequence with each cycle.

Ct value

The cycle number at which real-time PCR fluorescence crosses a threshold; it is inversely related to the amount of starting template, with lower values indicating more target.

FISH

Fluorescence in situ hybridization uses labeled probes to detect specific DNA sequences or copy-number changes on chromosomes, useful for rapid aneuploidy and translocation detection.

Universal RBC donor

Group O red blood cells lack A and B antigens and can be given to recipients of any ABO group; group AB plasma is the universal plasma donor.

Delayed hemolytic reaction

A transfusion reaction occurring 5 to 10 days after transfusion with falling hemoglobin, positive direct antiglobulin test, and a newly formed alloantibody.

TRALI

Transfusion-related acute lung injury presents with acute hypoxemia and bilateral pulmonary infiltrates within 6 hours of transfusion, often associated with donor anti-HLA or anti-neutrophil antibodies.

Irradiated blood components

Components treated with gamma irradiation to inactivate donor T lymphocytes, preventing transfusion-associated graft-versus-host disease in immunocompromised recipients.

Westgard 1-3s rule

A quality control rejection rule in which one control value exceeds the mean by more than three standard deviations, indicating random error and requiring run rejection.

Biosafety level 2

The containment level used for most clinical laboratories, requiring standard precautions plus limited access, biohazard signage, and biosafety cabinets for aerosol-generating procedures.

Beer-Lambert law

Absorbance equals molar absorptivity times path length times concentration; absorbance is directly proportional to concentration at a fixed wavelength and path length.

Coulter principle

Electrical impedance cell counting in which cells passing through an aperture displace conductive diluent, generating pulses proportional to cell volume for counting and sizing.

Ion-selective electrode

A sensor that measures the activity of a specific ion such as sodium or potassium; direct measurements are unaffected by protein, whereas indirect methods can be affected by hyperproteinemia.

Sensitivity

The proportion of truly diseased individuals who test positive, calculated as true positives divided by true positives plus false negatives.

Positive predictive value

The probability that a positive test result is correct, calculated as true positives divided by all positives; it rises as disease prevalence increases.

Coefficient of variation

A measure of method imprecision calculated as the standard deviation divided by the mean, multiplied by 100 and expressed as a percentage.

Bland-Altman plot

A method comparison plot of the difference between two methods against their mean, with limits of agreement at the mean difference plus or minus 1.96 standard deviations.