Adaptation of a Microdilution Procedure to the
            <i>Limulus</i>
            Lysate Assay for Endotoxin

Prior, Richard B.; Spagna, Vincent A.

doi:10.1128/jcm.10.3.394-395.1979

Cited by 15 publications

(6 citation statements)

References 1 publication

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“…The microdilution procedure was performed as previously described (8). Briefly, 0.05 ml of the 1:100 dilution used in the tube test was added to wells 1 and 2.…”

Section: Methodsmentioning

confidence: 99%

“…Despite numerous reports (1, 2, 4-6) describing modifications of the LAL assay which eliminate the need for tubes, most require complex materials and sophisticated equipment. Recently, we described a modification of the standard LAL tube assay in which microdilution plastic plates were used to quantitate lipopolysaccharide (8). The test was easy to perform, and interpretation of results was as definitive as the tube technique.…”

mentioning

confidence: 99%

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Comparative evaluation of the tube and microdilution Limulus lysate techniques for rapid presumptive diagnosis of gonococcal urethritis in men

Prior¹,

Spagna²

1980

J Clin Microbiol

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Eighty-one men with exudative urethritis were evaluated on initial visit for gonococcal urethritis by using the standard tube and newly developed microdilution Limulus amoebocyte lysate techniques. Serial dilutions of clinical specimens ranging from 1:100 to 1:102,400 were each tested, and results correlated with Gram stain and culture. Overall accuracy for predicting culture results was 98% for a dilution of 1:200 and 99% for a dilution of 1:400 for the tube and microdilution techniques, respectively. The microdilution technique predicted culture results in 98% of cases for dilutions ranging from 1:400 to 1:1,600, whereas the tube technique was as accurate for dilutions of only 1:100 and 1:200. The microdilution Limulus amoebocyte lysate technique was a rapid, reliable, sensitive, and economical diagnostic aid in the initial evaluation of exudative urethritis in men.

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“…The microdilution procedure was performed as previously described (8). Briefly, 0.05 ml of the 1:100 dilution used in the tube test was added to wells 1 and 2.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Comparative evaluation of the tube and microdilution Limulus lysate techniques for rapid presumptive diagnosis of gonococcal urethritis in men

Prior¹,

Spagna²

1980

J Clin Microbiol

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“…Previous attempts at instrument-assisted performance of LAL testing have included manual spectrophotometric methods (11,21) or the measurement of incorporated radioisotopes (15). Other modified procedures for the reading of LAL test endpoints or methods intended to conserve lysate have included the use of microdilution trays (17) or microslides (3). However, the MS-2 System provides the first procedure for automated spectrophotometric perfornance of the LAL tests.…”

Section: Discussionmentioning

confidence: 99%

Automation of the Limulus amoebocyte lysate test by using the Abbott MS-2 microbiology system

Jorgensen¹,

Alexander²

1981

Appl Environ Microbiol

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A rapid, automated method for the performance of the Limulus amoebocyte lysate endotoxin assay has been developed by using the Abbott MS-2 Microbiology System. This instrument automatically determines sequential changes in the optical density of up to 176 samples at 1or 5-min increments during a 1-h assay period. Graphic representation of optical density changes can be viewed on a cathode-ray tube or reproduced by using a hardcopy printer. Limulus amoebocyte lysate preparations that were obtained from different commercial producers and that had similar endotoxin sensitivities by the conventional gelation method varied somewhat in reactivity when determinations were based upon rate changes in optical density. Lysates from Associates of Cape Cod, Difco Laboratories, and M. A. Bioproducts were the most readily adaptable to the MS-2 System. Use of the MS-2 system increased the sensitivity of these preparations from 60to 250fold, and as little as 1 pg/ml was detected. Adaptation of the MS-2 instrument for this purpose provides an objective, reproducible, automated method for the performance of Limulus amoebocyte lysate tests on a variety of fluids.

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“…The most successful diagnostic use of the LAL test has been for detection of gram-negative bacterial meningitis, first reported by Nachum et al (11) and later confirmed by other investigators (5,14). Rapid detection of clinically significant gram-negative bacteriuria has also been described (3,4), and a reliable and simple method for detection of gonococcal urethritis by LAL assay has been reported (12,13,16). Kass (16) has defined clinically significant bacteriuria as urine containing more than lOs5 bacteria per ml.…”

mentioning

confidence: 96%

Rapid detection of Gram-negative bacteriuria by Limulus amoebocyte lysate assay

Nachum¹,

Shanbrom²

1981

J Clin Microbiol

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The Limulus amoebocyte lysate (LAL) test was evaluated for rapid detection of gram-negative bacteriuria in an adult patient population. Time to gelation of a standard LAL preparation was used as a measure of significant (greater than 10(5) bacteria per ml) gram-negative bacteriuria, and the results of 190 LAL assays were compared with quantitative urine cultures. Initially, 33 of 36 urine specimens containing greater than 10(5) gram-negative bacteria per ml were detected by LAL assay. The three false-negative LAL tests were the result of urine pH levels below the pH minimum for LAL gelation; neutralization of these urine specimens resulted in positive LAL assays and 100% correlation with culture results. All 36 bacteriuric urine specimens were LAL positive within 15 min, with the majority of assays (86.1%) being positive after only 10 min of incubation at 37 degrees C. These data compared favorably with gelation times of 15 min when 1 X 10(5) to 2 X 10(5) gram-negative bacteria per ml were added to sterile urine. Two urine samples obtained from male patients with culture-proven gonococcal urethritis yielded positive LAL assays. The LAL assay was shown to correctly differentiate 96.2% of urine specimens as containing less than 10(5) or greater than 10(5) gram-negative bacteria per ml. The results of this study have shown that the LAL test can be used as a rapid, simple, and reliable screening procedure for the diagnosis of clinically significant gram-negative bacteriuria.

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Adaptation of a Microdilution Procedure to the Limulus Lysate Assay for Endotoxin

Abstract: Endpoint determinations of endotoxin by the Limulus amoebocyte lysate assay have been facilitated by use of a microdilution procedure.

Cited by 15 publications

References 1 publication

Comparative evaluation of the tube and microdilution Limulus lysate techniques for rapid presumptive diagnosis of gonococcal urethritis in men

Comparative evaluation of the tube and microdilution Limulus lysate techniques for rapid presumptive diagnosis of gonococcal urethritis in men

Automation of the Limulus amoebocyte lysate test by using the Abbott MS-2 microbiology system

Rapid detection of Gram-negative bacteriuria by Limulus amoebocyte lysate assay

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