ASCP MLT flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- ABO reverse grouping
- Reverse grouping detects naturally occurring IgM antibodies in serum: group A has anti-B, group B has anti-A, group O has both, and group AB has neither.
- DAT positive significance
- A positive direct antiglobulin test shows IgG or complement coating red cells in vivo, suggesting autoimmune hemolysis, drug-induced hemolysis, or a hemolytic transfusion reaction.
- Rh immune globulin timing
- RhIG is given to Rh-negative mothers to prevent anti-D formation; it is most effective when administered within 72 hours after delivery of an Rh-positive infant.
- Acute hemolytic reaction
- Acute hemolytic transfusion reactions usually result from ABO incompatibility, causing fever, chills, flank pain, hemoglobinuria, and hypotension; stop the transfusion immediately.
- Platelet storage conditions
- Platelets are stored at 20–24°C with continuous gentle agitation for up to 5 days to maintain viability and function.
- Anion gap formula
- Anion gap equals sodium minus the sum of chloride and bicarbonate; the reference range is about 8–12 mmol/L and helps classify metabolic acidosis.
- Beer-Lambert law
- Absorbance equals molar absorptivity times path length times concentration, so absorbance is directly proportional to analyte concentration in solution.
- Corrected calcium formula
- Corrected calcium equals measured calcium plus 0.8 times (4.0 minus serum albumin), adjusting calcium for hypoalbuminemia.
- LDL Friedewald calculation
- LDL cholesterol equals total cholesterol minus HDL cholesterol minus triglycerides divided by 5; the formula is invalid when triglycerides exceed 400 mg/dL.
- Serum osmolality estimate
- Calculated osmolality equals 2 times sodium plus glucose divided by 18 plus BUN divided by 2.8, using mg/dL units.
- MCHC calculation
- MCHC equals hemoglobin times 100 divided by hematocrit; it reflects the average hemoglobin concentration in red cells and helps classify anemia.
- Corrected reticulocyte count
- Corrected reticulocyte count equals reticulocyte percentage times patient hematocrit divided by normal hematocrit, adjusting for anemia severity.
- DIC laboratory pattern
- Disseminated intravascular coagulation shows thrombocytopenia, prolonged PT and aPTT, low fibrinogen, and elevated D-dimer or fibrin degradation products.
- Iron deficiency pattern
- Iron deficiency anemia typically shows low ferritin, low serum iron, high TIBC, low transferrin saturation, and microcytic hypochromic red cells.
- Hematocrit from RBC and MCV
- Hematocrit equals red cell count in millions per microliter times MCV in femtoliters divided by 10.
- Coagulase test purpose
- Coagulase production distinguishes Staphylococcus aureus, which is coagulase positive, from most other staphylococci, which are coagulase negative.
- MacConkey lactose fermenters
- On MacConkey agar, lactose-fermenting gram-negative bacilli produce pink colonies, while non-lactose fermenters remain colorless or pale.
- Oxidase test positive organism
- Pseudomonas aeruginosa is oxidase positive, whereas Enterobacteriaceae are oxidase negative, helping guide preliminary bacterial identification.
- CSF bacterial meningitis pattern
- Bacterial meningitis typically shows increased neutrophils, low glucose, and high protein in cerebrospinal fluid, usually with a positive Gram stain.
- MRSA resistance mechanism
- Methicillin resistance in Staphylococcus aureus is mediated by the mecA gene, which encodes an altered penicillin-binding protein with reduced beta-lactam affinity.
- IgM primary response
- IgM is the first antibody class produced in a primary immune response and is efficient at complement activation and agglutination.
- Type I hypersensitivity
- Type I hypersensitivity is IgE-mediated and causes immediate reactions such as anaphylaxis, asthma, and allergic rhinitis after mast cell degranulation.
- ELISA principle
- Enzyme-linked immunosorbent assay uses an enzyme-labeled antibody or antigen; substrate conversion produces a measurable color signal proportional to target concentration.
- Hepatitis B surface antigen
- Hepatitis B surface antigen indicates current hepatitis B infection, whether acute or chronic, and is the first serologic marker to appear.
- Urine nitrite positive meaning
- A positive urine nitrite test suggests infection by nitrate-reducing gram-negative bacteria, commonly Escherichia coli, but can be negative with frequent voiding.
- Leukocyte esterase significance
- Leukocyte esterase detects white blood cells in urine and supports urinary tract infection or inflammation when positive.
- Hyaline cast composition
- Hyaline casts are composed of Tamm-Horsfall mucoprotein and can appear in normal urine after exercise, fever, or dehydration.
- Urine specific gravity
- Specific gravity reflects urine concentration; higher values indicate concentrated urine, while values near 1.010 suggest isosthenuria.
- Westgard 2-2s rule
- The 2-2s rule flags two consecutive control values beyond the same 2 standard deviation limit, indicating a systematic error.
- Order of draw principle
- Collect blood culture, then coagulation citrate tube, serum tube, heparin tube, EDTA tube, and glycolytic inhibitor tube to minimize additive contamination.
- Delta check purpose
- A delta check compares a patient's current result with previous values and flags large changes that may indicate specimen error or clinical deterioration.
- Critical value reporting
- Critical values are life-threatening results that must be reported promptly to the responsible clinician and documented.