Abstract
A patient with squamous cell carcinoma of the lung and a serum rheumatoid factor (RF) of 1:1,280 had a positive cerebrospinal fluid (CSF) latex agglutination test (LAT) for cryptococcal antigen, in culture-negative, India-ink-negative CSF. Pretreatment of the sample of CSF with 2-mercaptoethanol (2-ME) ablated the antigen titer and established the presence of a false-positive LAT, whereas CSF pretreated with dithiothreitol (DTT) and pronase continued to yield a false-positive result. The differing ability of pronase, DTT, and 2-ME to eliminate interfering substances from CSF has not been previously described. Moreover, because RF is unlikely to cross the blood-brain barrier, the authors postulated that malignant disease was responsible for the patient's false-positive LAT in CSF. Hence, the authors report the case to emphasize that false-positive LAT results in CSF are unlikely to be produced by RF and to underscore the benefit of using enzymatic and sulfhydryl-reducing agents when the validity of the initial test results are in doubt. Such a procedure will optimize the chances of accurately identifying false-positive LAT results in CSF.
Original language | English (US) |
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Pages (from-to) | 381-384 |
Number of pages | 4 |
Journal | American journal of clinical pathology |
Volume | 96 |
Issue number | 3 |
DOIs | |
State | Published - 1991 |
Externally published | Yes |
Keywords
- 2-Mercaptoethanol
- Cryptococcal meningitis
- Dithiothreitol
- Pronase
- Rheumatoid factor
ASJC Scopus subject areas
- Pathology and Forensic Medicine