Kuwait MOH Medical Laboratory Technician cheat sheet

Reference interval = central 95% of a healthy population (2.5th–97.5th percentile); results outside it are not automatically pathologic.

Anion gap = Na⁺ − (Cl⁻ + HCO₃⁻); normal 8–12 mmol/L; elevated gap suggests unmeasured anions (ketoacidosis, lactate, uremia, salicylate).

Beer-Lambert law: A = ε × b × c; absorbance is linear with concentration only within the assay's validated linear range.

Friedewald LDL = TC − HDL − (TG/5), valid only when TG < 400 mg/dL; use direct or Martin-Hopkins method above that.

Enzymatic glucose (hexokinase or glucose oxidase) is reference; fluoride-oxalate tubes inhibit glycolysis but are unsuitable for urea and enzymes.

Creatinine by Jaffe reaction is subject to positive interference from ketoacids, cephalosporins, and glucose; enzymatic creatinine is more specific.

Cardiac troponin I or T is the preferred necrosis marker; CK-MB lacks cardiac specificity and rises after skeletal muscle injury.

Hemolysis falsely raises K⁺, LDH, AST, and phosphate and falsely lowers glucose, bilirubin, and troponin depending on platform.

MCV = (Hct × 10)/RBC (fL); MCH = Hb/RBC × 10 (pg); MCHC = Hb/Hct × 100 (g/dL); MCHC > 36 g/dL suggests spherocytosis, lipemia, or cold agglutinin.

EDTA (lavender) is the anticoagulant for CBC; fill to the line because underfilling concentrates EDTA and shrinks cells, falsely lowering MCV and Hct.

Corrected reticulocyte % = observed retic % × (patient Hct / normal Hct); absolute retic count = retic % × RBC.

PT/INR monitors warfarin (extrinsic, factor VII); APTT monitors unfractionated heparin (intrinsic, factors VIII, IX, XI, XII).

Platelet count 150–450 × 10⁹/L; pseudothrombocytopenia from platelet clumping in EDTA requires a citrate or heparin re-draw.

D-dimer has high sensitivity and low specificity; a negative result with low pretest probability helps exclude venous thromboembolism.

Sickle cell: HbS on alkaline electrophoresis; solubility (sickledex) is a screening test only; HPLC or DNA confirms.

Iron deficiency shows low ferritin, low serum iron, high TIBC, low saturation; anemia of chronic disease shows low iron, low TIBC, normal-to-high ferritin.

Gram-positive cocci in clusters, catalase positive, coagulase positive = Staphylococcus aureus; coagulase negative = Staphylococcus epidermidis or other CoNS.

Gram-negative lactose fermenters on MacConkey appear pink; non-fermenters (Pseudomonas) are colorless; oxidase positive supports Pseudomonas.

Beta-hemolysis on blood agar with bacitracin sensitivity suggests Streptococcus pyogenes (group A); bile-esculin positive, salt tolerant = Enterococcus.

Acid-fast stain (Ziehl-Neelsen) detects mycobacteria; culture on Löwenstein-Jensen or MGIT; Mycobacterium tuberculosis is a slow grower (2–6 weeks).

HBsAg indicates infection; anti-HBs indicates immunity; anti-HBc IgM indicates acute infection; HBeAg indicates high infectivity.

HIV screening uses 4th-generation Ag/Ab assay; reactive results require supplemental differentiation (HIV-1/2 antibody differentiation) and nucleic acid testing.

KOH preparation with calcofluor white shows fungal hyphae and yeast; germ tube test is positive for Candida albicans.

Malaria diagnosis: Giemsa-stained thick film for detection, thin film for species identification; P. falciparum shows multiple rings and banana-shaped gametocytes.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value depends on prevalence; a highly sensitive test is best for ruling out disease.

ELISA formats: direct (antigen detection), indirect (antibody detection), sandwich (antigen capture), competitive (small molecules).

Antinuclear antibody (ANA) by indirect immunofluorescence is a screening test; anti-dsDNA and anti-Sm are specific for SLE.

Rheumatoid factor is an IgM anti-IgG antibody; anti-CCP is more specific for rheumatoid arthritis.

Complement: C3 and C4 are consumed in active SLE; low C3 with low C4 supports disease activity.

Syphilis serology: non-treponemal (RPR, VDRL) for screening and monitoring; treponemal (TPPA, FTA-ABS, EIA) for confirmation.

Type I hypersensitivity is IgE mediated; type II is antibody against cell-bound antigen; type III is immune complex; type IV is T-cell mediated (delayed).

Cross-reactivity and heterophile antibodies can cause false positives; blocking reagents and re-testing on alternate platforms help resolve them.

ABO: A has anti-B, B has anti-A, O has both, AB has neither; group O is universal red cell donor, AB is universal plasma donor.

Rh(D) negative patients must receive Rh(D) negative red cells; anti-D can cause hemolytic disease of the newborn.

Antibody screen uses indirect antiglobulin test (IAT); a positive screen requires identification by panel cells and crossmatch.

Crossmatch: immediate spin (ABO), then AHG phase; electronic crossmatch is allowed only when the antibody screen is negative and no history of clinically significant antibodies.

Coombs test: direct (DAT) detects antibody or complement on patient red cells; indirect (IAT) detects antibody in serum.

Transfusion reaction: stop the transfusion, keep the line open with saline, notify blood bank, return the bag and tubing, and send post-transfusion samples.

Febrile non-hemolytic reaction is the most common; acute hemolytic reaction is usually due to ABO incompatibility and can cause DIC and renal failure.

Platelets are stored at 20–24 °C with agitation; red cells at 1–6 °C; fresh frozen plasma at ≤ −18 °C.

First-morning midstream urine is preferred; delay > 2 hours at room temperature causes cell lysis, bacterial overgrowth, and pH rise.

Dipstick blood detects hemoglobin and myoglobin; a positive blood with no red cells on microscopy suggests hemoglobinuria or myoglobinuria.

Urine pH 4.5–8.0; alkaline urine with crystals may indicate struvite (infection) stones; acidic urine favors uric acid stones.

Hyaline casts are nonspecific; red cell casts indicate glomerulonephritis; white cell casts suggest pyelonephritis; muddy brown casts suggest acute tubular necrosis.

CSF: bacterial meningitis shows neutrophilic pleocytosis, low glucose, high protein; viral shows lymphocytic pleocytosis with normal glucose.

Pleural fluid: Light's criteria (protein ratio > 0.5, LDH ratio > 0.6, or LDH > 2/3 upper normal) classify exudate.

Synovial fluid: > 50,000 WBC/µL suggests septic arthritis; 2,000–50,000 suggests inflammatory arthritis; < 2,000 suggests non-inflammatory.

Westgard rules: 1-2s warning; 1-3s rejection; 2-2s rejection; R-4s rejection; 4-1s rejection; 10x rejection.

Levey-Jennings chart plots daily QC values against mean ± 2SD and ± 3SD; trends and shifts indicate systematic error.

Internal QC is daily precision monitoring; external quality assessment (proficiency testing) compares performance across laboratories.

Biological safety cabinet Class II is used for infectious aerosols; Class I protects the operator only; Class III is fully enclosed.

Chemical hygiene: SDS (Safety Data Sheet) is available for every hazardous chemical; eyewash and shower within 10 seconds' travel.

Sharps go in puncture-resistant containers; biohazard waste is autoclaved or incinerated per local regulation.

Specimen labeling requires two patient identifiers at the bedside; mislabeled specimens must be rejected and recollected.

Critical values must be reported to the responsible clinician and documented with read-back.

Spectrophotometry: monochromator selects wavelength; absorbance is measured against a reagent blank; cuvette path length is typically 1 cm.

Ion-selective electrodes measure Na⁺, K⁺, Cl⁻, Ca²⁺ by potentiometry; indirect ISE dilutes the sample and is affected by hyperlipidemia or hyperproteinemia.

Flow cytometry uses forward scatter (size) and side scatter (granularity); fluorescence-tagged antibodies identify cell populations.

HPLC separates by retention time; used for HbA1c, hemoglobin variants, and therapeutic drug monitoring.

Atomic absorption or ICP-MS measures trace elements; flame photometry is used for sodium and potassium.

Coefficient of variation (CV) = (SD/mean) × 100; lower CV means better precision.

Analytical sensitivity is the lowest detectable concentration; analytical specificity is the ability to measure only the intended analyte.

Calibration establishes the relationship between signal and concentration; it must be verified with independent controls.

PCR: denaturation ~95 °C, annealing ~50–65 °C, extension ~72 °C; each cycle doubles the target.

Real-time PCR quantifies target using fluorescent probes (TaqMan, molecular beacons); Ct value is inversely proportional to target amount.

Contamination control: unidirectional workflow (reagent → sample → amplification), UNG, and separate pre- and post-amplification areas.

Sanger sequencing is the gold standard for single-gene variants; next-generation sequencing (NGS) enables panel and exome testing.

Nucleic acid amplification tests (NAAT) detect viral RNA/DNA (HIV, HBV, HCV, SARS-CoV-2) and are more sensitive than culture or antigen tests.

Mass spectrometry (MALDI-TOF) identifies bacteria by protein fingerprint; used for rapid organism identification in microbiology.

Pharmacogenomics: CYP2C19 variants affect clopidogrel activation; HLA-B*57:01 predicts abacavir hypersensitivity.

Kuwait MOH licenses laboratory staff and registers medical laboratories; practice must comply with MOH and Ministry of Health regulations and the Kuwait Medical Laboratory Practice standards.

Patient confidentiality is protected; results are released only to authorized persons, and unauthorized disclosure is a disciplinary and legal matter.

Informed consent is required before invasive sampling (e.g., bone marrow, amniocentesis) and before genetic testing.

Medical waste is segregated at the point of generation; sharps, infectious, and chemical waste follow MOH and Kuwait Environment Public Authority rules.

Notifiable diseases (e.g., tuberculosis, measles, hepatitis, HIV) must be reported to the MOH public health authority.

Mandatory continuing education and competency assessment maintain licensure; scope of practice is limited to the licensed discipline.

Errors and adverse events are reported through the institutional incident system; near misses are reported without blame.

Research involving human samples requires ethics committee approval and consent; anonymized residual samples may be used only per approved protocol.