Leucine Aminopeptidase (LAP) Test: Principle, Procedure, Results
LAP (leucine aminopeptidase) test: principle, procedure, and expected results, and how it works alongside PYR to identify catalase-negative Gram-positive cocci.
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Gram-Positive Cocci
Staphylococcus, Streptococcus, Enterococcus, Micrococcus — organisms, diseases, and identification tests
Gram Positive Cocci of Medical Importance
Gram positive cocci by arrangement, clusters, chains, pairs, and tetrads, covering Staphylococcus, Streptococcus, Enterococcus, and Micrococcus with key identification tests
Staphylococcus saprophyticus: Properties, Pathogenesis, and Lab Diagnosis
Staphylococcus saprophyticus morphology, urease and adhesin virulence factors, and the novobiocin test used to confirm this cause of UTI in young women
Staphylococcus vs. Micrococcus: Key Differences and Tests
How to tell Staphylococcus and Micrococcus apart: morphology, catalase, bacitracin, furazolidone, and microdase test results compared.
Staphylococcus vs. Streptococcus: Differences and Comparison Table
Compare Staphylococcus and Streptococcus by morphology, catalase test, hemolysis pattern, and diseases caused, with a full comparison table.
Catalase Test: The 3-Second Test That Separates Staph from Strep, and Five Ways It Lies
Bubbles in 3 seconds means Staphylococcus. But red blood cells bubble, nichrome loops bubble, and enterococci grown on blood agar bubble weakly. Learn what the catalase test actual...
Blood Agar: Composition, Preparation, and How to Read Hemolysis
Blood agar composition and preparation, how to tell alpha, beta, gamma, and alpha-prime hemolysis apart, and the double-zone target pattern, with a colony-appearance table for 20+...
Novobiocin Susceptibility Test: How One Disk Tells S. saprophyticus From a Contaminant
A 5 ug novobiocin disk separates S. saprophyticus, a real cause of UTI in young women, from S. epidermidis, usually just skin contamination. Full procedure, the corrected 16mm brea...
Bacitracin Test: Principle, Procedure, Results
Bacitracin susceptibility test principle, procedure, and zone interpretation for presumptive identification of Streptococcus pyogenes (Group A Strep)
Optochin Sensitivity Test: Principle, Procedure, Results
Optochin test principle, procedure, and the 14mm zone cutoff used with bile solubility to confirm Streptococcus pneumoniae
Biochemical Tests Used to Identify Bacteria in the Microbiology Laboratory
A complete guide to biochemical tests used in bacterial identification — 40+ tests organised by category with principle, positive result, and organisms identified. Includes IMViC,...
Staphylococcus aureus: Properties, Pathogenesis & Lab Diagnosis
Staphylococcus aureus morphology, virulence factors and the diseases they cause, plus catalase, coagulase and other tests used for lab diagnosis.
Coagulase Test: Principle, Procedure, Results
Learn the coagulase test step by step — slide and tube methods, results interpretation, MRSA limitations, and reporting guide for clinical labs.