Biomaterial Database

Usefulness of LAL assay for rapid detection of gram-negative bacteriuria. 1987

R Nachum

LAL assay is a rapid and reliable and easy to perform and interpret urine screen for clinically significant gram-negative bacteriuria. Chromogenic assays are rapid (5 min) and obviate problems associated with gel endpoints, such as inadvertant dissolution of the gel, either during incubation or reading. LAL urine screening is characterized by both high positive and negative predictive values. LAL urine assay identifies gram-negative urinary tract infections by measuring urine endotoxin content as an index for significant numbers of urinary tract pathogens, thus eliminating large numbers of false-positive tests characteristic of other urine screening methods. Screening urine for greater than or equal to 10(5) CFU/ml appears to be an acceptable criterion for defining a UTI in patient populations with low prevalence rates (2-10%). Thus, LAL urine assay may have potential usefulness for screening of asymptomatic populations, such as pregnant women and the elderly.

UI	MeSH Term	Description	Entries
D008033	Limulus Test	Sensitive method for detection of bacterial endotoxins and endotoxin-like substances that depends on the in vitro gelation of Limulus amebocyte lysate (LAL), prepared from the circulating blood (amebocytes) of the horseshoe crab, by the endotoxin or related compound. Used for detection of endotoxin in body fluids and parenteral pharmaceuticals.	Limulus Tests,Test, Limulus,Tests, Limulus
D002863	Chromogenic Compounds	Colorless, endogenous or exogenous pigment precursors that may be transformed by biological mechanisms into colored compounds; used in biochemical assays and in diagnosis as indicators, especially in the form of enzyme substrates. Synonym: chromogens (not to be confused with pigment-synthesizing bacteria also called chromogens).	Chromogenic Compound,Chromogenic Substrate,Chromogenic Substrates,Compound, Chromogenic,Compounds, Chromogenic,Substrate, Chromogenic,Substrates, Chromogenic
D004731	Endotoxins	Toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.	Endotoxin
D005188	False Negative Reactions	Negative test results in subjects who possess the attribute for which the test is conducted. The labeling of diseased persons as healthy when screening in the detection of disease. (Last, A Dictionary of Epidemiology, 2d ed)	False Negative Reaction,Reaction, False Negative,Reactions, False Negative
D005189	False Positive Reactions	Positive test results in subjects who do not possess the attribute for which the test is conducted. The labeling of healthy persons as diseased when screening in the detection of disease. (Last, A Dictionary of Epidemiology, 2d ed)	False Positive Reaction,Positive Reaction, False,Positive Reactions, False,Reaction, False Positive,Reactions, False Positive
D006090	Gram-Negative Bacteria	Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.	Gram Negative Bacteria
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001437	Bacteriuria	The presence of bacteria in the urine which is normally bacteria-free. These bacteria are from the URINARY TRACT and are not contaminants of the surrounding tissues. Bacteriuria can be symptomatic or asymptomatic. Significant bacteriuria is an indicator of urinary tract infection.	Bacteriurias