MT POST flashcards

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

Hemolysis effect on potassium

Rupture of red cells releases intracellular potassium into serum, falsely elevating measured potassium. Specimens with visible hemolysis should be recollected before reporting potassium, LDH, or AST.

Order of draw rationale

Tube order prevents additive carryover between tubes. Citrate and serum tubes are drawn before EDTA and glycolytic inhibitor tubes because contamination with potassium EDTA or fluoride would distort coagulation and chemistry results.

Citrate tube fill requirement

Light blue sodium citrate tubes must be filled to the marked volume. Underfilling raises the anticoagulant-to-blood ratio, falsely prolonging PT and aPTT; overfilling also alters the ratio.

Delta check

A comparison of a current result with the same patient's previous result. A difference exceeding the laboratory-defined limit prompts review of specimen identity or integrity before the result is released.

Beer-Lambert law

Absorbance equals molar absorptivity times path length times concentration. Photometric assays rely on this linear relationship; results above the linear range require dilution and reanalysis.

Westgard 1-3s rule

A single control value exceeding the mean by more than three standard deviations is a rejection rule. It indicates random error and the run should not be reported until resolved.

Westgard 2-2s rule

Two consecutive control values exceed the same two-standard-deviation limit, or one value exceeds plus 2s and another exceeds minus 2s. This signals systematic error and rejects the run.

Sandwich immunoassay

Two antibodies bind different epitopes of the analyte: a capture antibody and a labeled detection antibody. Signal increases with analyte concentration, so it suits large molecules such as proteins.

Competitive immunoassay

Labeled antigen competes with patient antigen for a limited number of antibody binding sites. Signal is inversely proportional to analyte concentration, making this format suitable for small haptens.

Schistocytes significance

Fragmented red cells seen on a blood film suggest mechanical hemolysis from microangiopathy, prosthetic valves, or disseminated intravascular coagulation. They warrant urgent clinical correlation.

CLIA test complexity categories

Tests are classified as waived, moderate complexity, or high complexity. A laboratory's certificate must cover the highest complexity category of testing it performs, and personnel qualifications differ by category.

Proficiency testing rule

PT specimens must be tested as routine patient samples by laboratory personnel. Sharing or referring PT samples to another laboratory is prohibited and can jeopardize the laboratory's CLIA certification.

Critical value read-back

The person receiving a critical result repeats the value back to the reporting laboratorian. Both names, the value, and the time are documented to confirm accurate communication.

Root cause analysis

A structured investigation identifying the underlying system causes of an adverse event or nonconformance, rather than blaming individuals, so that corrective actions prevent recurrence.

Standard precautions

Infection control practices applied to all patients regardless of diagnosis, treating blood and body fluids as potentially infectious. They include hand hygiene, gloves, gowns, masks, and eye protection as indicated.

PPE removal order

Remove gloves first, then goggles or face shield, gown, and mask or respirator last. Hand hygiene follows removal, since the respirator is removed by the straps without touching the front.

Needlestick first response

Wash the puncture site with soap and water without squeezing or scrubbing, report the exposure immediately, and proceed with post-exposure evaluation for HIV, hepatitis B, and hepatitis C.

Bloodborne Pathogens Standard

The OSHA regulation requiring a written exposure control plan, hepatitis B vaccination offered at no cost, appropriate PPE, hazard labeling, and annual employee training.

Safety Data Sheet

A standardized document describing a chemical's hazards, handling, storage, spill response, and first aid. It must be readily accessible to staff who handle the substance.

RACE fire response

Rescue anyone in danger, Alarm activation, Confine the fire by closing doors, and Evacuate or Extinguish. Extinguisher use follows the PASS technique: pull, aim, squeeze, sweep.

HIPAA minimum necessary

Only the minimum protected health information needed for a purpose may be accessed or disclosed. It limits unnecessary exposure of patient data during routine operations and communications.

HIPAA breach notification

Following discovery of a breach of unsecured protected health information, affected individuals must be notified without unreasonable delay and no later than 60 days after discovery.

Two patient identifiers

Before specimen collection or any procedure, verify identity using at least two identifiers such as full name and date of birth. The patient should state them when able.

Error disclosure obligation

Laboratory errors affecting patient care must be reported through the incident system and disclosed according to policy. Concealment violates professional and institutional ethical standards.

Qualified interpreter use

Communication with limited-English-proficiency patients should use a qualified medical interpreter, not family members, especially for consent. Teach-back confirms that the message was understood.

Hematocrit to hemoglobin relation

Hematocrit is roughly three times the hemoglobin concentration in g/dL. A marked deviation from this rule suggests a red cell abnormality or a measurement error.

MCV and anemia classification

Mean corpuscular volume classifies anemia as microcytic (below 80 fL), normocytic (80 to 100 fL), or macrocytic (above 100 fL). This guides the differential and further testing.

Respiratory acidosis

A primary disorder with decreased pH and increased pCO2 caused by hypoventilation. Renal compensation raises bicarbonate over days, partially restoring pH toward normal.

Metabolic acidosis

A primary disorder with decreased pH and decreased bicarbonate. Compensation is hyperventilation, which lowers pCO2; the anion gap helps identify the cause.

Troponin as cardiac marker

Cardiac troponin I and T are highly specific markers of myocardial injury. They rise within hours of injury and remain elevated for days, supporting acute coronary syndrome evaluation.

PT versus aPTT monitoring

Prothrombin time assesses the extrinsic and common pathways and monitors warfarin therapy via the INR. Activated partial thromboplastin time assesses the intrinsic pathway and monitors unfractionated heparin.

Urine cast significance

Casts form in renal tubules and indicate a renal origin of disease rather than a lower urinary tract process. Red cell casts suggest glomerulonephritis and are clinically significant.