False positive latex tests for cryptococcal antigen in cerebrospinal fluid.

Hay, R. J.; Mackenzie, D. W. R.

doi:10.1136/jcp.35.2.244

Cited by 21 publications

(10 citation statements)

References 8 publications

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“…Direct microscopic examination is a rapid but quite insensitive test and strongly depends on the operator's skills. The latex agglutination test is a more sensitive method but may still yield false-positive and false-negative results with either serum or CSF (2)(3)(4)11). Moreover, the simple culture of CSF samples on Sabouraud agar is time-consuming; in fact, at least 4 days is necessary to detect positive cultures of C. neoformans (7).…”

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Development of a Nested PCR for Detection of Cryptococcus neoformans in Cerebrospinal Fluid

Rappelli¹,

Are

Casu³

et al. 1998

J Clin Microbiol

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We report the development of a nested-PCR-based assay for the detection of Cryptococcus neoformans in cerebrospinal fluid. The specificity and sensitivity of the test were assessed. The technique was then applied to 40 cerebrospinal fluid samples. We obtained positive reactions for all 21 clinical samples from patients who had been previously diagnosed as having cryptococcal meningitis by conventional techniques and negative reactions for all 19 negative controls. Nested PCR is here compared with other diagnostic methods currently used in patients’ follow-up exams during anticryptococcal therapy.

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confidence: 99%

Development of a Nested PCR for Detection of Cryptococcus neoformans in Cerebrospinal Fluid

Rappelli¹,

Are

Casu³

et al. 1998

J Clin Microbiol

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“…The latex agglutination test (LAT) for the detection of cryptococcal capsular polysaccharide antigen in serum and cerebrospinal fluid (CSF) is a rapid and reliable serologic method for the diagnosis of cryptococcosis (3,9,10). Results of the LAT can be used as the basis for making decisions concerning prognosis and therapy (2,4,6,9).…”

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Experience with the use of pronase to eliminate interference factors in the latex agglutination test for cryptococcal antigen

Gray

Roberts

1988

J Clin Microbiol

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Cryptococcal antigen titers of 70 cerebrospinal fluid and 57 serum specimens from patients suspected of having cryptococcosis were determined both before and after treatment with pronase. Median titers of cerebrospinal fluid specimens before and after treatment were 128 and 128, respectively; mean geometric titers of these specimens before and after treatment were 102 and 204, respectively. Median titers of the serum specimens before and after treatment were 16 and 512, respectively; mean geometric titers of these specimens before and after treatment were 19 and 631, respectively. The modified latex agglutination test did not detect antigen in any of 50 cerebrospinal fluid and 51 serum specimens from patients not suspected of having cryptococcosis. These results suggest that the pronase modification increases the sensitivity of the latex agglutination test and that the modification be routinely incorporated into it.

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“…The percentage of false-negatives (5-10 O/o) could probably be lowered with the recently described ELISA techniques whose sensitivity threshold is below 10 ng/ml(l2,49), however, it is to be feared that the number offalse-positives would increase. With the latex test itself, the rate of false-positives in CSF is 5-100h (3,23,31). These titers usually, but by no means always, are quite low, and may or may not be due to the presence of rheumatoid factors.…”

Section: Cns Cryptococcosis: Pathognomonic Findings In Csfmentioning

confidence: 99%

Diagnosis of Cryptococcosis and Monitoring of Chemotherapy

Scholer

1985

Mycoses

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Summary: Despite great variation in the clinical symptoms and routine CSF findings, diagnosis of cryptococcosis of the CNS is quite easy thanks to high reliability of direct microscopy Indian ink and culture of cryptococcosis neoformans in the CSF and of the test for cryptococcal antigen. The crucial point is just to think of cryptococcosis. Monitoring of chemotherapy is more difficult, and this is particularly true for the decision when to discontinue treatment with a minimum risk of relapse. The absolute requirement is a negative CSF culture in 3 consecutive samples taken at weekly intervals. The other parameters such as antigen titer, Indian ink, CSF glucose and cerebral foci in CT, are not reliable taken alone. If, however, 2 or more of the respective findings are still pathological, this must remind us to go beyond the before‐mentioned minimum Oeriod. Patients receiving long‐acting corticosteroids generally need prolonged treatment only hydrocortisone should be used to combat the “acute” adverse reactions to amphotericin B. The standard period of a given chemotherapy e.g., 6 weeks in the case of the combination of amphotericin B and flucytosine should be considered a rough guide, whilst the actual length must depend on the conditions of the individual patients. Zusammenfassung: Trotz großer Variabilität der klinischen Symptome und der meisten Liquorbefunde ist die Diagnose einer Cryptococcose des Zentralnervensystems verhältnismäßig einfach. Dies dank der hohen Zuverlässigkeit des direktmikroskopischen und kulturellen Befundes von Cryptococcus neoformans im Liquor und des Nachweises von Cryptococcus‐Antigen. In den meisten Fällen geht es hauptsächlich darum, an die Möglichkeit einer Cryptococcose zu denken. Die Beurteilung des Heilungsverlaufs unter Chemotherapie, besonders der Behandlungsdauer, ist bedeutend schwieriger. Die Mindestanforderung für ein Absetzen der Behandlung ist ein negativer Kulturbefund in mindestens drei aufeinanderfolgenden, wöchentlichen Liquorproben. Die übrigen Parameter wie Direktmikroskopie, Antigentiter, Liquorzucker und zerebrale Herde in der Computertomographie sind, jeder für sich allein, nicht entscheidend, mahnen aber zu einer Verlängerung der Behandlung, wenn zwei oder mehr der betreffenden Befunde noch pathologisch sind. Patienten, die langwirkende Corticosteroide erhalten haben, benötigen eine verhältnismäßig lange Chemotherapie. Zur Bekämpfung der “akuten” Nebenwirkungen von Amphotericin B sollte ausschließlich Hydrocortison verwendet werden. Die Standarddauer einer gegebenen Chemotherapie z. B. sechs Wochen im Falle der Kombination Amphotericin B plus 5‐Fluonytosin sollte eher als Minimum betrachtet werden und nicht als starre Regel.

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False positive latex tests for cryptococcal antigen in cerebrospinal fluid.

Cited by 21 publications

References 8 publications

Development of a Nested PCR for Detection of Cryptococcus neoformans in Cerebrospinal Fluid

Development of a Nested PCR for Detection of Cryptococcus neoformans in Cerebrospinal Fluid

Experience with the use of pronase to eliminate interference factors in the latex agglutination test for cryptococcal antigen

Diagnosis of Cryptococcosis and Monitoring of Chemotherapy

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