CSF Culture Change
Effective July 13, 2009, Warde Medical Laboratory will modify the Comprehensive Virus Detection (CVD) protocol for testing cerebrospinal fluid (CSF) specimens. Our experience and the published experience from ARUP Laboratories (1) indicates that culturing CSF specimens after PCR testing
a. Provides no additional
b. Adds needless cost
c. Delays the time to a final result
No Additional Diagnostic Benefit
Our experience and that of the published paper from ARUP (1) indicates that PCR testing is more sensitive than CSF culture for the viruses listed in Table 1. Since the inception of the Warde CVD protocol in 2006, our laboratory has not isolated a virus from a PCR-negative specimen.
Delayed Time to Result
Culturing PCR-negative CSF specimens significantly delays the final report to the client. In our laboratory,
- The mean time to result for CSF PCR testing is about 24 hours from the time the specimen is received in the laboratory.
- The final result for negative cultures is not available for 14 days.
- Many of our interfaced clients have chosen not to receive preliminary reports. Therefore, the client may not know that the specimen is PCR-negative until the culture has been finalized.
- For PCR-positive CSF specimens, the laboratory notifies Warde Client Services and Client Services calls the client.
- Generating a final result when PCR testing is complete will benefit the patient by providing diagnostic information in a more timely manner.
Table 1. Viruses recovered from 22,394 CSF submitted to ARUP Laboratories over an 11 year period. Viruses were recovered from 1270 cultures (5.7%) during this time.
|Percent of Total||Mean Time|
|Herpes Simplex Virus||16||0.7%||6 days|
|Cytomegalovirus||3||0.01%||2 days *|
|Varicella Zoster Virus||1||0.004%||4 days *|
|Adenovirus||1||0.004%||4 days *|
|No Virus Isolated||21,124||94.3%||14 days *|
*Historical and current isolation data from Warde Medical Laboratory.
We recognize that there may be special circumstances where a physician suspects the presence of rare but cultivable viruses that cause viral meningoencephalitis that are not part of our routine CSF testing algorithm (e.g., influenza, parainfluenza, measles, and mumps). In these special instances, the physician may order individual PCR tests- or he/she may contact the Director of the Virology service to request a CSF viral culture.
Please contact Dr. Wiedbrauk (800-876-6522) if you have any questions.