Laboratory Procedures and Diagnostics Flashcards

What is the primary purpose of Gram staining in microbiology?

Answer: To classify bacteria as gram-positive or gram-negative based on cell wall characteristics

Gram staining differentiates bacteria by cell wall composition: gram-positive bacteria appear purple, while gram-negative bacteria appear pink/red.

What does a positive rapid strep test (RADT) result indicate?

Answer: Group A Streptococcus antigen is present in the throat specimen

A positive rapid antigen detection test for strep detects Group A Streptococcus antigens in the specimen, indicating streptococcal pharyngitis.

Which laboratory value is used to monitor long-term blood glucose control in patients with diabetes?

Answer: Hemoglobin A1c (HbA1c)

HbA1c reflects the average blood glucose over the previous 2-3 months by measuring glycated hemoglobin, making it the gold standard for monitoring diabetes management.

What is the correct protocol for labeling a laboratory specimen?

Answer: Label the container at the patient's side immediately after collection, with patient name, DOB, date, and time

Specimens must be labeled at the patient's side immediately after collection with at least two patient identifiers, date, and time to prevent mislabeling errors.

A patient's PT/INR result is 3.5 and they are on warfarin therapy. The therapeutic range for most conditions is INR 2.0-3.0. What is the most appropriate next step?

Answer: Notify the provider of the elevated INR as it exceeds the therapeutic range

An INR of 3.5 exceeds the therapeutic range and increases bleeding risk; the provider must be notified promptly for potential warfarin dose adjustment.

What does the term 'sensitivity' mean in the context of a laboratory diagnostic test?

Answer: The test's ability to correctly identify patients with the disease (true positives)

Sensitivity is the proportion of true positives correctly identified — a highly sensitive test rarely misses patients who actually have the disease.