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Discover the key differences between thick and thin blood smears. Learn about their uses in medical diagnosis and how they are performed.
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Learn about the Lysine Decarboxylase test used to differentiate bacteria based on their ability to produce decarboxylase enzymes. This article covers the test procedure, how to interpret results and what they mean.
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The catalase test procedure identifies bacteria that produce the catalase enzyme. The enzyme is present in nearly all organisms and, when exposed to oxygen, catalyzes the breakdown of hydrogen peroxide to oxygen and water. Bacteria that utilize aerobic respiration produce H2O2 as a toxic byproduct. They make the catalase enzyme a virulence factor to neutralize…
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Microbiologists use the Methyl red test to identify bacteria that can ferment glucose to stable-acid by-products. Methyl red (MR) is a pH indicator that turns red below 4.4, orange between 4.4 and 6.2, and yellow above 6.2. Methyl red (2-[[4-(dimethylamino)phenyl]diazenyl]benzoic acid) is a dark red crystalline azo dye. The MR-VP medium provides the glucose substrate,…
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The indole test is a biochemical test demonstrating a bacteria’s ability to break down the amino acid tryptophan to indole. Microbiologists use the test to narrow down on Enterobacteria that can break down the amino acid. The test is commonly used after gram staining to narrow down on specific gram-negative or gram-positive bacteria. In clinical…
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Learn about the Rivalta test, a simple and inexpensive method to differentiate between transudates and exudates. Discover its procedure, principle, and interpretation.
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Discover Pandy’s test, a simple method to detect globulin in cerebrospinal fluid. Learn about its procedure, principle, and interpretation.
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Routine venipuncture is the process of drawing blood from a vein during phlebotomy. Standard operating procedures (SOPs) should be adhered to when collecting blood samples. There are multiple reasons for drawing blood from a vein. These include laboratory testing, getting rid of excess blood, treatment, and for blood transfusion. Veins are preferred over arteries because…
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The Sahli method, also referred to as the acid hematin method, is a technique used to measure the amount of haemoglobin in blood. In this process, blood is mixed with a dilute solution of hydrochloric acid (HCl) to convert hemoglobin into a brown-colored substance called acid hematin. The resulting solution is then diluted until its…
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The Coagulase test is a biochemical assessment that checks for the ability of bacteria to produce coagulase enzyme. Microbiologists primarily use the test for differentiating coagulase-positive Staphylococcus aureus from other coagulase-negative Staphylococci. Bacteria produce coagulase enzyme, a virulent factor that interacts with fibrinogen attached to the host’s cell—interacting with fibrinogen results in the formation of…