MLT Registration cheat sheet

ABO forward typing uses anti-A and anti-B reagents; reverse typing uses A1 and B cells; discrepancy requires resolution before transfusion.

Rh typing: weak D testing is required for all initially D-negative patients; D-negative females of childbearing age receive RhIG at 28 weeks and within 72 hours of delivery.

Crossmatch: immediate spin crossmatch is acceptable if antibody screen is negative; AHG crossmatch is required if screen is positive or history of clinically significant antibody.

Antibody screen uses 3-cell panel (I, II, III) at AHG phase; positive screen requires identification panel and antigen-negative units.

Blood components: packed RBCs stored at 1-6°C for 35-42 days; platelets at 20-24°C with agitation for 5 days; FFP at -18°C or colder for 1 year.

Transfusion reaction: stop transfusion, maintain IV access, return bag and tubing to blood bank, check clerical errors, and report to physician.

Acute hemolytic reaction: most common cause is clerical error; signs include fever, chills, flank pain, hemoglobinuria, and DIC.

Febrile nonhemolytic reaction: most common overall; caused by cytokines or leukocyte antibodies; treated with antipyretics and leukoreduced products for future.

Granulocyte transfusion: requires ABO-compatible, HLA-matched or crossmatch-compatible donor; irradiated to prevent GVHD.

Beer-Lambert law: A = εbc; absorbance is directly proportional to concentration and path length.

Enzymatic glucose: hexokinase method is reference; glucose oxidase produces H2O2 detected by peroxidase; fluoride oxalate inhibits glycolysis.

Creatinine: Jaffe reaction uses alkaline picrate; kinetic alkaline picrate reduces interference; enzymatic method is more specific.

BUN: urease converts urea to ammonia and CO2; ammonia measured by coupled enzyme or conductivity; urea nitrogen × 2.14 = urea.

Liver enzymes: ALT more liver-specific than AST; ALP elevated in biliary obstruction and bone disease; GGT confirms hepatobiliary source of ALP.

Cardiac troponin I and T are most specific markers of myocardial injury; rise 3-6 hours, peak 12-24 hours, remain elevated 5-14 days.

Electrolytes: sodium by indirect or direct ion-selective electrode; pseudohyponatremia occurs with hyperlipidemia or hyperproteinemia in indirect ISE.

Acid-base: Henderson-Hasselbalch pH = 6.1 + log([HCO3-]/(0.03 × pCO2)); anion gap = Na - (Cl + HCO3), normal 8-12 mEq/L.

Quality control: Levey-Jennings chart; Westgard rules: 1-2s warning, 1-3s rejection, 2-2s rejection, R-4s rejection, 4-1s rejection, 10x rejection.

PT measures extrinsic and common pathway (factors VII, X, V, II, fibrinogen); INR = (PT patient / PT normal)^ISI.

APTT measures intrinsic and common pathway (factors XII, XI, IX, VIII, X, V, II, fibrinogen); heparin therapeutic range 1.5-2.5 times normal.

Mixing study: correction of prolonged PT/APTT with normal plasma indicates factor deficiency; failure to correct indicates inhibitor (e.g., lupus anticoagulant, factor VIII inhibitor).

D-dimer: fibrin degradation product; elevated in DIC, VTE, pregnancy, surgery; negative D-dimer with low clinical probability helps exclude VTE.

DIC: prolonged PT/APTT, low platelets, low fibrinogen, elevated D-dimer; schistocytes on smear; treat underlying cause.

Heparin monitoring: APTT or anti-Xa; protamine sulfate reverses heparin; vitamin K reverses warfarin; fresh frozen plasma or PCC for urgent reversal.

Platelet function: bleeding time is insensitive; PFA-100 closure time; von Willebrand disease shows prolonged PFA-100 and low vWF antigen/activity.

Factor VIII and IX: hemophilia A and B; prolonged APTT corrects with mixing; factor activity levels determine severity (<1% severe, 1-5% moderate, 5-40% mild).

Lupus anticoagulant: prolonged APTT that does not correct with mixing; associated with thrombosis, not bleeding; confirm with hexagonal phase phospholipid or platelet neutralization.

Complete blood count: hemoglobin, hematocrit, RBC indices (MCV, MCH, MCHC), WBC with differential, platelet count; MCV = (Hct × 10)/RBC in millions.

Anemia classification by MCV: microcytic (<80 fL) iron deficiency, thalassemia, anemia of chronic disease; normocytic (80-100 fL) acute blood loss, hemolysis, renal; macrocytic (>100 fL) B12/folate deficiency, alcohol, liver disease.

Iron studies: iron deficiency shows low ferritin, low serum iron, high TIBC, low saturation; anemia of chronic disease shows low iron, low TIBC, normal/high ferritin.

Reticulocyte count: corrected reticulocyte count = reticulocyte % × (patient Hct / normal Hct); reticulocyte production index adjusts for maturation.

Hemoglobin electrophoresis: HbA, HbA2, HbF; beta-thalassemia trait shows elevated HbA2 (>3.5%); sickle cell trait shows HbAS.

Platelet count: thrombocytopenia <150,000/µL; pseudothrombocytopenia due to platelet clumping in EDTA; repeat in citrate tube.

WBC differential: neutrophils 50-70%, lymphocytes 20-40%, monocytes 2-8%, eosinophils 1-4%, basophils 0-1%; absolute neutrophil count <500/µL indicates severe neutropenia.

Bone marrow: myeloid-to-erythroid ratio 2:1 to 4:1; iron stores assessed by Prussian blue stain; ring sideroblasts in sideroblastic anemia.

Hemolysis markers: elevated reticulocyte count, indirect bilirubin, LDH, decreased haptoglobin; direct antiglobulin test (DAT) distinguishes immune from non-immune.

Antibody structure: IgG monomer, IgM pentamer, IgA dimer with J chain; IgG crosses placenta; IgM is first responder and fixes complement efficiently.

Complement pathways: classical (IgG/IgM-antigen complexes), alternative (microbial surfaces), lectin (mannose-binding lectin); all converge on C3 convertase and membrane attack complex.

Hypersensitivity: type I IgE mast cell (anaphylaxis), type II antibody-mediated (hemolytic transfusion reaction), type III immune complex (SLE), type IV delayed T-cell (tuberculin).

Autoimmune diseases: ANA sensitive for SLE; anti-dsDNA and anti-Sm specific; rheumatoid factor in RA; anti-CCP more specific.

Immunodeficiency: Bruton agammaglobulinemia (X-linked, no B cells), DiGeorge syndrome (T-cell deficiency, hypocalcemia), severe combined immunodeficiency (SCID).

Tumor markers: AFP (hepatocellular, yolk sac), CEA (colorectal), CA-125 (ovarian), PSA (prostate), CA 19-9 (pancreatic).

Transplant rejection: hyperacute (preformed antibodies), acute (cellular, days to weeks), chronic (fibrosis, months to years); HLA typing and crossmatch prevent hyperacute.

Serology: ELISA for screening, Western blot for confirmation, indirect immunofluorescence for ANA; false positives in syphilis screening require treponemal confirmatory test.

Cytokines: IL-1, IL-6, TNF-alpha are proinflammatory; IL-4 and IL-10 are anti-inflammatory; interferon-gamma activates macrophages.

Gram stain: gram-positive purple, gram-negative pink; cocci in clusters (Staphylococcus), chains (Streptococcus), pairs (Neisseria); rods (Enterobacteriaceae, Pseudomonas).

Culture media: blood agar (hemolysis), MacConkey (gram-negative, lactose fermentation), chocolate agar (fastidious organisms), mannitol salt (Staphylococcus aureus).

Catalase and coagulase: Staphylococcus aureus is catalase-positive, coagulase-positive; coagulase-negative staphylococci are less pathogenic.

Streptococcus classification: beta-hemolytic group A (S. pyogenes) bacitracin sensitive; group B (S. agalactiae) hippurate positive; alpha-hemolytic S. pneumoniae optochin sensitive.

Urinary tract infection: colony count ≥10^5 CFU/mL in midstream urine; mixed flora suggests contamination; E. coli most common.

Blood culture: two sets from different sites before antibiotics; volume is critical; incubate 5 days; positive Gram stain reported immediately.

Antibiotic susceptibility: disk diffusion (Kirby-Bauer) and MIC (broth dilution, E-test); CLSI breakpoints; MRSA resistant to oxacillin/methicillin.

Mycobacteria: acid-fast stain (Ziehl-Neelsen); culture on Lowenstein-Jensen or liquid media; slow growth 2-6 weeks.

Fungal: KOH prep for dermatophytes; germ tube test for Candida albicans; India ink for Cryptococcus neoformans.

Order of draw: blood cultures, light blue (citrate), serum tube (red/gold), heparin (green), EDTA (lavender), fluoride oxalate (gray).

Tourniquet: apply 3-4 inches above venipuncture site; release within 1 minute to avoid hemoconcentration and potassium elevation.

Venipuncture site: antecubital fossa; median cubital vein preferred; avoid bruised, scarred, or edematous areas; never draw from an arm with dialysis fistula.

Needle gauge: 21G for routine adult venipuncture; 23G for small veins or pediatric; butterfly needle for fragile veins.

Hemolysis: avoid excessive suction, small needle, shaking tubes; hemolysis falsely elevates potassium, LDH, AST.

Specimen handling: EDTA tubes invert 8-10 times; citrate tubes invert 3-4 times; do not shake; separate serum/plasma within 2 hours when required.

Capillary puncture: fingerstick for adults, heelstick for infants; wipe away first drop; avoid squeezing to prevent hemolysis and tissue fluid contamination.

Needlestick prevention: use safety-engineered devices; do not recap needles; dispose in sharps container; report exposure immediately.

Patient identification: two identifiers (name and date of birth or medical record number); label tubes at bedside after collection.

Quality assurance: includes quality control, proficiency testing, and quality assessment; CLIA requires proficiency testing for regulated analytes.

CLIA complexity: waived, moderate, high; waived tests have low risk and simple methodology; moderate/high require documented training and competency.

Quality control: run two levels of control per shift; Westgard rules for acceptance; document corrective action for failures.

Proficiency testing: unknown samples from approved provider; results must be within acceptable limits; failure triggers corrective action and possible sanctions.

Turnaround time (TAT): preanalytical, analytical, postanalytical; monitor and improve; critical values reported within defined time.

Budget: fixed vs variable costs; cost per test includes reagents, labor, overhead; productivity measured by tests per FTE.

Inventory: FIFO (first in, first out); monitor expiration dates; par levels to avoid stockouts; reagent lot-to-lot verification.

Safety: OSHA bloodborne pathogens standard; exposure control plan; hepatitis B vaccination offered; chemical hygiene plan; fire safety.

Accreditation: CAP, Joint Commission; inspections; document control; competency assessment for all personnel.