PetriKey

Lab method

Coagulase test

S. aureus clue among staphylococci

koh-AG-yoo-lays

labenzymestaphcoagulase

High-yield clue

Coagulase positive is a classic S. aureus clue.

Overview

A biochemical test concept used in teaching algorithms to distinguish coagulase-positive Staphylococcus aureus from coagulase-negative staphylococci.

Classification

  • Biochemical test
  • Staphylococcus differentiation

Lab & identification clues

  • Clotting vocabulary
  • Tube/slide test concepts

Associations

  • Staphylococcus aureus
  • Coagulase-negative staphylococci

Commonly confused with

  • Catalase test
  • Oxidase test

Your notes

Original concept summary for coursework. Sources checked: OpenStax Microbiology 2e and NCBI Bookshelf Medical Microbiology; reviewed 2026-06. Describes vocabulary and interpretation concepts only; not a lab protocol and not for handling specimens or identifying patient isolates.

OpenStax: Microbiology 2e staining, media, and biochemical-test foundationssourceNCBI Bookshelf: Medical Microbiology diagnostic concept foundationssource