Clinical Laboratory Techniques & Procedures Flashcards
7 cards from real CLT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Clinical Laboratory Techniques & Procedures flashcards as text
During electrophoresis of serum proteins on cellulose acetate, the band that migrates the farthest toward the anode at pH 8.6 is:
Answer: Albumin
Albumin carries the greatest net negative charge at pH 8.6 and therefore migrates farthest toward the positive electrode during serum protein electrophoresis.
Which anticoagulant is found in a light-blue (sodium citrate) tube and works by:
Answer: Chelating calcium ions required for coagulation
Sodium citrate binds (chelates) ionized calcium, preventing activation of calcium-dependent clotting factors required for both intrinsic and extrinsic pathways.
The principle of ion-selective electrode (ISE) technology used in modern electrolyte analyzers depends on:
Answer: A semi-permeable membrane selective for a specific ion producing a measurable potential
ISEs use an ion-selective membrane that generates a Nernstian potential proportional to the activity (concentration) of a specific ion in the sample.
A technologist running a urine pregnancy test (hCG lateral flow immunoassay) reports a false-negative result in a patient known to be pregnant. The most likely cause is:
Answer: High-dose hook effect from extremely elevated hCG
The hook effect occurs when extremely high hCG concentrations saturate both capture and detection antibodies, preventing sandwich complex formation and causing a false-negative.
Which of the following would be the best action when a reagent blank (reagent with no sample) reads higher absorbance than expected on a spectrophotometer?
Answer: Investigate the reagents for contamination or degradation
An unexpectedly high reagent blank suggests reagent contamination, wrong reagent preparation, or reagent degradation, all of which require investigation before reporting.
When performing a gram stain, safranin is used as the:
Answer: Counterstain to color gram-negative organisms pink
Safranin is the counterstain applied after decolorization; it stains gram-negative bacteria (and decolorized gram-positives) pink/red for visualization.
A laboratory measures linearity by testing five concentrations across the analytical measurement range. The method is considered linear when:
Answer: The relationship between measured and expected values is described by a straight line with r² ≥ 0.99
Linearity is confirmed when measured values across the concentration range follow a straight-line relationship, typically assessed by r² ≥ 0.99 and minimal deviation from expected values.