Validation of laboratory screening criteria for herpes simplex virus testing of cerebrospinal fluid

Utilization of a Meningitis/Encephalitis PCR panel at the University Hospital Basel - a retrospective study to develop a diagnostic decision rule

Background

The Biofire® FilmArray® Meningitis/Encephalitis (ME) PCR panel covers 14 viral, bacterial, and fungal pathogens and has been implemented in many institutions worldwide. Post-marketing studies indicate a reduced sensitivity and overutilization underscoring the need for a more targeted usage. The aim of our study is to describe the utilization of the ME panel and to develop a diagnostic-stewardship based decision rule.

Materials

Adult patients, who underwent CSF analysis with the ME panel between August 2016 and June 2021 at the University Hospital Basel, were included. Demographic, clinical, microbiological, and laboratory data were extracted from the electronic health record. Factors associated with a positive ME panel result were identified, and a decision rule was developed to potentially optimize the diagnostic yield and reduce the number of unnecessary tests.

Results

1,236 adult patients received at least one panel in the observed period, of whom 106 panels tested positive (8.6%). The most frequently observed pathogens were Varicella Zoster Virus (VZV, 27%), Streptococcus pneumoniae (19%), Enterovirus (16%), Herpes simplex Virus 1/2 (16%), and Human Herpesvirus 6 (HHV-6, 13%). Fever, vomiting, headache, and photophobia were more frequently present in test positive patients as were significantly higher CSF leukocytes and protein concentrations. When simulating a decision rule based on CSF leukocytes and protein concentration, only 35% of all patients would have qualified for a ME panel tests, thereby increasing the positivity rate to 22.7%. 10 of 106 positive ME panels would have been missed, only involving HHV-6 and VZV (6 and 4 cases, respectively). As these subjects were either severely immunocompromised or had clinical features of shingles we propose extending the testing algorithm by including those criteria.

Conclusion

The ME panel positivity rate at our institution was similar as previously published. Our results highlight the need for diagnostic-stewardship interventions when utilizing this assay by implementing a stepwise approach based on a limited number of clinical and laboratory features. This decision rule may improve the pretest probability of a positive test result, increase the quality of test utilization, and reduce costs.

A retrospective review of empiric acyclovir prescribing practices for suspected viral central nervous system infections: A single-centre study

Background

Acyclovir has an important role in the treatment of viral central nervous system (CNS) infection, especially herpes simplex virus (HSV)-1 encephalitis. It is therefore used broadly as empiric therapy for many patients who present to the hospital with symptoms of a possible neurologic infection. We sought to review our practices in acyclovir prescribing, deprescribing, and associated investigations for the clinical syndromes it treats.

Methods

Through a retrospective chart review, we identified patients prescribed acyclovir for a possible CNS infection upon admission to Vancouver General Hospital between January 1, 2019, and December 31, 2019. Patient demographics, signs, symptoms, and comorbidities were taken from admission consultation notes or discharge summaries; their investigations, including laboratory tests and imaging, were also recorded. The primary purpose was to describe the appropriateness of empiric acyclovir use in suspected meningoencephalitis cases.

Results

Among the 108 patients treated with acyclovir, 94 patients had an indication for starting empiric treatment for encephalitis or meningitis. There was suspicion and workup for encephalitis alone in 76 patients. Among discharge diagnoses, the most common was delirium of a different identified source (18 cases), followed by unknown/other (15 cases). There were seven patients whose CSF viral PCR test was positive for HSV or varicella-zoster virus (VZV); three of them had HSV-1 encephalitis. There were two total adverse events recorded attributed to acyclovir; both cases were of mild acute kidney injury.

Conclusion

We found that in many patients, acyclovir was not necessary or could have been stopped earlier, avoiding toxicity and drug costs.

Rational Use of Microbiological Tests in the Diagnosis of Central Nervous System Infections Using Restrictive Criteria: a Retrospective Study

Microbiological testing in general and in the setting of central nervous system (CNS) infection in particular are often excessive, leading to superfluous laboratory work and costs. In this regard, restrictive criteria, named Reller criteria, have been developed to reduce unnecessary CSF herpes simplex virus 1 (HSV-1) PCR testing when suspecting encephalitis.

Viral meningitis in Sudanese children: Differentiation, etiology and review of literature

Diagnosis of viral meningitis (VM) is uncommon practice in Sudan and there is no local viral etiological map. We therefore intended to differentiate VM using standardized clinical codes and determine the involvement of herpes simplex virus types-1 and 2 (HSV-1/2), varicella zoster virus, non-polio human enteroviruses (HEVs), and human parechoviruses in meningeal infections in children in Sudan. This is a cross-sectional hospital-based study. Viral meningitis was differentiated in 503 suspected febrile attendee of Omdurman Hospital for Children following the criteria listed in the Clinical Case Definition for Aseptic/Viral Meningitis. Patients were children age 0 to 15 years. Viral nucleic acids (DNA/RNA) were extracted from cerebrospinal fluid (CSF) specimens using QIAamp® UltraSens Virus Technology. Complementary DNA was prepared from viral RNA using GoScriptTM Reverse Transcription System. Viral nucleic acids were amplified and detected using quantitative TaqMan® Real-Time and conventional polymerase chain reactions (PCRs). Hospital diagnosis of VM was assigned to 0%, when clinical codes were applied; we considered 3.2% as having VM among the total study population and as 40% among those with proven infectious meningitis. Two (0.4%) out of total 503 CSF specimens were positive for HSV-1; Ct values were 37.05 and 39.10 and virus copies were 652/PCR run (261 × 103/mL CSF) and 123/PCR run (49.3 × 103/mL CSF), respectively. Other 2 (0.4%) CSF specimens were positive for non-polio HEVs; Ct values were 37.70 and 38.30, and the approximate virus copies were 5E2/PCR run (~2E5/mL CSF) and 2E2/PCR run (~8E4/mL CSF), respectively. No genetic materials were detected for HSV-2, varicella zoster virus, and human parechoviruses. The diagnosis of VM was never assigned by the hospital despite fulfilling the clinical case definition. Virus detection rate was 10% among cases with proven infectious meningitis. Detected viruses were HSV-1 and non-polio HEVs. Positive virus PCRs in CSFs with normal cellular counts were seen.

Diagnostic Stewardship as a Team Sport: Interdisciplinary Perspectives on Improved Implementation of Interventions and Effect Measurement

Diagnostic stewardship aims to deliver the right test to the right patient at the right time and is optimally combined with antimicrobial stewardship to allow for the right interpretation to translate into the right antimicrobial at the right time. Laboratorians, physicians, pharmacists, and other healthcare providers have an opportunity to improve the effectiveness of diagnostics through collaborative activities around pre-analytical and post-analytical periods of diagnostic testing. Additionally, special considerations should be given to measuring the effectiveness of diagnostics over time. Herein, we perform a narrative review of the literature on these potential optimization opportunities and the temporal factors that can yield changes in diagnostic effectiveness. Our objective is to inform on these considerations to ensure enhanced value through improved implementation and measurement of effectiveness for local stakeholder metrics and/or clinical outcomes research.

Faster infection diagnostics for intensive care unit (ICU) patients

INTRODUCTION

: The patient admitted to intensive care units (ICU) is critically ill, to some extent immunosuppressed, with a high risk of infection, sometimes by multidrug-resistant microorganisms. In this context, the intensivist expects from the microbiology service quick and understandable information so that appropriate antimicrobial treatment for that particular patient and infection can be initiated.

AREAS COVERED

: In this review of recent literature (2015-2021), we identified diagnostic methods for the most prevalent infections in these patients through a search of the databases Pubmed, evidence-based medicine online, York University reviewers group, Cochrane, MBE-Trip, and Sumsearch using the terms: adult, clinical laboratory techniques, critical care, early diagnosis, microbiology, molecular diagnostic techniques, spectrometry and metagenomics.

EXPERT OPINION

: There has been an exponential surge in diagnostic systems used directly on blood and other samples to expedite microbial identification and antimicrobial susceptibility testing of pathogens. Few studies have thus far assessed their clinical impact; final outcomes will also depend on preanalytical and post-analytical factors. Besides, many of the resistance mechanisms cannot yet be detected with molecular techniques, which impairs the prediction of the actual resistance phenotype.

Nonetheless, this is an exciting field with much yet to explore.

Evaluation of the selection of cerebrospinal fluid testing in suspected meningitis and encephalitis

Diagnostic stewardship interventions can decrease unnecessary antimicrobial therapy and microbiology laboratory resources and costs. This retrospective cross-sectional study evaluated factors associated with inappropriate initial cerebrospinal fluid (CSF) testing in patients with suspected community-acquired meningitis or encephalitis. In 250 patients, 202 (80.8%) and 48 (19.2%) were suspected meningitis and encephalitis, respectively. 207 (82.8%) patients had inappropriate and 43 (17.2%) appropriate testing. Any inappropriate CSF test was greatest in the immunocompromised (IC) group (n = 54, 91.5%), followed by non-IC (n = 109, 80.1%) and HIV (n = 44, 80%). Ordering performed on the general ward was associated with inappropriate CSF test orders (adjOR 2.81, 95% CI [1.08-7.34]). Laboratory fee costs associated with excessive testing was close to $300,000 per year. A stepwise algorithm defining empiric and add on tests according to CSF parameters and patient characteristics could improve CSF test ordering in patients with suspected meningitis or encephalitis.

S1 guidelines "lumbar puncture and cerebrospinal fluid analysis" (abridged and translated version)

Introduction

Cerebrospinal fluid (CSF) analysis is important for detecting inflammation of the nervous system and the meninges, bleeding in the area of the subarachnoid space that may not be visualized by imaging, and the spread of malignant diseases to the CSF space. In the diagnosis and differential diagnosis of neurodegenerative diseases, the importance of CSF analysis is increasing. Measuring the opening pressure of CSF in idiopathic intracranial hypertension and at spinal tap in normal pressure hydrocephalus constitute diagnostic examination procedures with therapeutic benefits.Recommendations (most important 3-5 recommendations on a glimpse): The indications and contraindications must be checked before lumbar puncture (LP) is performed, and sampling CSF requires the consent of the patient.Puncture with an atraumatic needle is associated with a lower incidence of postpuncture discomfort. The frequency of postpuncture syndrome correlates inversely with age and body mass index, and it is more common in women and patients with a history of headache. The sharp needle is preferably used in older or obese patients, also in punctures expected to be difficult.In order to avoid repeating LP, a sufficient quantity of CSF (at least 10 ml) should be collected. The CSF sample and the serum sample taken at the same time should be sent to a specialized laboratory immediately so that the emergency and basic CSF analysis program can be carried out within 2 h.The indication for LP in anticoagulant therapy should always be decided on an individual basis. The risk of interrupting anticoagulant therapy must be weighed against the increased bleeding risk of LP with anticoagulant therapy.As a quality assurance measure in CSF analysis, it is recommended that all cytological, clinical-chemical, and microbiological findings are combined in an integrated summary report and evaluated by an expert in CSF analysis.

Conclusions

In view of the importance and developments in CSF analysis, the S1 guideline "Lumbar puncture and cerebrospinal fluid analysis" was recently prepared by the German Society for CSF analysis and clinical neurochemistry (DGLN) and published in German in accordance with the guidelines of the AWMF (https://www.awmf.org). /uploads/tx_szleitlinien/030-141l_S1_Lumbalpunktion_und_Liquordiagnostik_2019-08.pdf). The present article is an abridged translation of the above cited guideline. The guideline has been jointly edited by the DGLN and DGN.

Diagnostic challenges of central nervous system infection: extensive multiplex panels versus stepwise guided approach

BACKGROUND

Cerebrospinal fluid (CSF) testing is a key component for the diagnosis of central nervous system (CNS) infections. Current meningitis and encephalitis management guidelines agree on the need for CSF molecular testing in combination with other direct and indirect biological testing, both in CSF and blood. Multiplex molecular tests have been developed to reduce turnaround times and facilitate the diagnostic approach.

OBJECTIVES

We aim to discuss the role of multiplex molecular panels in the management of CNS infections.

SOURCES

The MEDLINE database and the grey literature have been searched for relevant articles.

CONTENT

New molecular multiplex panels are being developed to simultaneously detect a large array of neuropathogens in CSF. Although one of these assays has been US Food and Drug Administration-approved, extensive analytical and clinical validation is still missing, and suboptimal performance related issues have been raised. Its use has been associated with decreased costs, reduced length of hospital stay and reduced antiviral therapy administration in retrospective, industry-sponsored studies. The pros and cons of this multiplex syndromic approach are discussed in this narrative review.

IMPLICATIONS

Molecular multiplex CNS infection diagnosis panels have been developed and present several attractive features, including ease of use and low turnaround time. However, suboptimal analytical performances render these tests difficult to use without additional confirmatory tests. Such panels are not comprehensive nor adapted to all situations, depending on the epidemiological or clinical context. Overall, available data in the literature currently do not support the use of a multiplex PCR panel in clinical routine as a 'stand-alone' molecular assay. Except in restricted laboratory capacity settings where such easy-to-use multiplex panels offer the diagnostic means that would otherwise not be available, the stepwise testing approach remains a more rational option. Serological testing both in blood and CSF should not be neglected, but it represents essential complementary tools regarding some neuropathogens.

Assessment of Diagnostic Yield of Nonculture Infection Testing on Cerebrospinal Fluid in Immune-Competent Children

IMPORTANCE

Nonculture infection tests of cerebrospinal fluid (CSF) samples using polymerase chain reaction and antigen or antibody assays are frequently ordered on lumbar puncture specimens concurrently with routine CSF cell counts, but the value of CSF infection testing in otherwise healthy children is unknown.

OBJECTIVE

To determine the value of nonculture CSF infection testing in immune-competent children with normal CSF cell counts.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study reviewed screening and diagnostic tests in the electronic medical record system of a large academic tertiary care children's hospital. Records of children aged 0.5 to 18.9 years (n = 4083) who underwent lumbar puncture (n = 4811 procedures) in an inpatient or outpatient facility of Children's Hospital of Philadelphia between July 1, 2007, and December 31, 2016, were reviewed. Those with indwelling CSF shunts or catheters; those with active or past oncologic, immunologic, or rheumatologic conditions; or those taking immune-suppressing medications were excluded from analysis. This study was conducted from July 20, 2017, to March 13, 2019.

MAIN OUTCOMES AND MEASURES

Outcome variables included frequency of nonculture CSF infection testing and frequency of positive results in the entire cohort, and among those with normal cell counts. Normal cell counts were defined as CSF white blood cell counts lower than 5 cells/μL and CSF red blood cell counts lower than 500 cells/μL.

RESULTS

In total, 4811 lumbar puncture procedures were performed on 4083 unique children, with a median (range) age of 7.4 (0.5-18.9) years, 2537 boys (52.7%), and 3331 (69.2%) with normal CSF cell counts. At least 1 nonculture CSF infection test was performed on 1270 lumbar puncture specimens with normal cell counts (38.1%; 95% CI, 36%-40%), and more tests were performed in the summer months. Only 18 (1.4%; 95% CI, 0.9%-2.2%) of 1270 lumbar puncture specimens with normal cell counts had at least 1 nonculture infection test with a positive result; 2 of these 18 children required clinical intervention for their positive results, but each also had other clear clinical signs of infection.

CONCLUSIONS AND RELEVANCE

Nonculture CSF infection testing appeared to be common in immune-competent children with normal CSF cell counts, but positive results were uncommon and were not independently associated with clinical care; delaying the decision to send nonculture infection tests until CSF cell counts are available could reduce unnecessary diagnostic testing and medical costs, which may improve value-based care.

Laboratory Diagnosis of Neonatal Herpes Simplex Virus Infections

Herpes simplex virus (HSV) is a common and often benign infection in humans; although it less commonly affects newborns, infection in this age group can be devastating. Newborns often present with nonspecific clinical findings, making timely and accurate diagnosis of infection critical. A wide variety of tests are available for detecting herpes simplex virus infection, but only a subset are useful and validated in the newborn population. The current review summarizes available diagnostic testing for neonatal disease, including discussing limitations, unmet needs, and emerging data on molecular testing methods.

Missing Cases of Herpes Simplex Virus (HSV) Infection of the Central Nervous System When the Reller Criteria Are Applied for HSV PCR Testing: a Multicenter Study

Previous studies suggested that herpes simplex virus (HSV) PCR testing can be safely deferred in patients with normal cerebrospinal fluid (CSF) white blood cell (WBC) counts and protein levels as long as they are older than 2 years of age and are not immunocompromised, the so-called Reller criteria. In this multicenter study, we retrospectively assessed the validity of these screening criteria in our setting. A total of 4,404 CSF specimens submitted for HSV PCR testing to the respective microbiology laboratories at the participating hospitals between 2012 and 2018 were included. Six commercially available HSV PCR assays were used across the participating centers. Ninety-one of the 4,404 CSF specimens (2.1%) tested were positive for HSV DNA (75 samples for HSV-1 and 16 for HSV-2). Nine patients failed to meet the Reller criteria, of whom seven were deemed to truly have HSV encephalitis. Overall, no significant correlation between HSV PCR cycle threshold (C_T ) values and WBC counts or total protein levels was found. In addition, median HSV PCR C_T s were comparable between patients who met the Reller criteria and those who did not (P = 0.531). In summary, we show that HSV DNA may be detected in CSF specimens with normal WBC and protein levels collected from immunocompetent individuals older than 2 years with HSV encephalitis. Nevertheless, the data also indicate that the number of cases detected could be lowered at least by half if CSF specimens with borderline WBC counts (4 cells/mm³) as well as children of any age are systematically tested.

Herpes Simplex Virus Type 2 Myelitis: Case Report and Review of the Literature

Non-traumatic myelopathies can result from a wide spectrum of conditions including inflammatory, ischemic, and metabolic disorders. Here, we describe the case of a 60-year old immunocompetent woman who developed acute back pain followed by rapidly ascending flaccid tetraparesis, a C6 sensory level, and sphincter dysfunction within 8 h. Acyclovir and steroids were started on day 2 and herpes simplex virus type 2 (HSV-2) was confirmed by polymerase chain reaction in cerebrospinal fluid. Magnetic resonance imaging revealed a bilateral anterior horn tractopathy expanding from C2 to T2 and cervicothoracic cord swelling. Screening for paraneoplastic antibodies and cancer was negative. Neurophysiology aided in the work-up by corroborating root involvement. Recovery was poor despite early initiation of antiviral treatment, adjuvant anti-inflammatory therapy, and neurorehabilitation efforts. The clinical course, bilateral affection of the anterior horns, and early focal atrophy on follow-up magnetic resonance imaging take a necrotizing myelitis potentially caused by intraneuronal spread of the virus into consideration. Further, we summarize the literature on classical and rare presentations of HSV-2 myeloradiculitis in non-immunocompromised patients and raise awareness for the limited treatment options for a condition with frequent devastating outcome.

Cost-Effectiveness Study of Criteria for Screening Cerebrospinal Fluid To Determine the Need for Herpes Simplex Virus PCR Testing

The absence of markers of inflammation in the cerebrospinal fluid (CSF) commonly predicts the absence of herpes simplex virus (HSV) central nervous system (CNS) infection. Consequently, multiple authors have proposed and validated criteria for deferring HSV PCR testing of CSF in immunocompetent hosts with normal CSF white blood cell and protein levels (≤5 cells/mm³ and ≤50 mg/dl, respectively). Hosts are considered immunocompetent if they are ≥2 years old and have not had HIV or an organ transplant. Adoption of the criteria may erroneously exclude HSV-infected persons from a necessary diagnostic test or, alternatively, reduce the costs associated with HSV tests with minimal to no effect on patient care. Little is known about the cost-effectiveness of this approach. A decision analysis model was developed to evaluate the adoption of criteria for screening HSV tests of CSF. Estimates of input parameter values combined available literature with a multiyear multisite review at two of the largest health care systems in the United States. Adoption of criteria to screen for HSV test need proved cost-effective when less than 1 in 200 patients deferred from testing truly had an HSV CNS infection. Similar to prior studies, none of the deferred cases had HSV encephalitis (n = 3120). Adoption of these criteria in the United States would save an estimated $127 million ($95 million to $158 million [±25%]) annually. The model calculations remained robust to variation in test cost, prevalence of HSV infection, and random variation to study assumptions. The adoption of criteria to screen HSV PCR tests in CSF represents a cost-effective approach.

Criteria to Screen Molecular Tests for the Diagnosis of Herpes Simplex Virus in the Central Nervous System have no Propensity to Harm

Objectives:

Investigators have ruled out herpes simplex virus (HSV) infection without the detection of herpes simplex deoxyribonucleic acid in cerebrospinal fluid (CSF) (i.e., HSV polymerase chain reaction [PCR]) by laboratory (normal CSF white blood cell count and protein) and clinical criteria (age ≥2 years, no history of human immunodeficiency virus or solid-organ transplant). Compared to HSV PCR of all samples, the algorithm saves money in test costs and may decrease exposure to acyclovir by illustrating the low probability that the patient has HSV. Concern exists that algorithm use may cause harm through alteration of empiric acyclovir treatment in patients with true HSV central nervous system infection.

Methods:

All Department of Veterans Affair's patients with a positive HSV PCR of the CSF between 2000 and 2013 were identified and their medical records reviewed to determine the extent and possible impact of omitted HSV PCR testing by the algorithm.

Results:

Of 6357 total results, 101 patients had a positive CSF HSV PCR in the study period. Among the positive CSF HSV PCR results, the algorithm excluded 7 (7%) from PCR testing. Record review indicated these seven patients not tested by the algorithm with a positive CSF HSV PCR were considered by their attending physician not to have active HSV.

Conclusion:

The algorithm to screen HSV tests had no propensity to harm.

Clinical and Laboratory Findings That Differentiate Herpes Simplex Virus Central Nervous System Disease from Enteroviral Meningitis

Background. It can be difficult for clinicians to distinguish between the relatively benign enteroviral (EnV) meningitis and potentially lethal herpes simplex virus (HSV) central nervous system (CNS) disease. Very limited evidence currently exists to guide them. Objective. This study sought to identify clinical features and cerebrospinal fluid (CSF) findings associated with HSV CNS disease. Methods. Given that PCR testing often is not immediately available, this chart review study sought to identify clinical and cerebrospinal fluid (CSF) findings associated with HSV meningitis over a 6-year period. In cases where PCR was not performed, HSV and EnV were assigned based on clinical criteria. Results. We enrolled 166 consecutive patients: 40 HSV and 126 EnV patients. HSV patients had a mean 40.4 versus 31.3 years for EnV, p = 0.005, seizures 21.1% versus 1.6% for EnV, p < 0.001, altered mental status 46.2% versus 3.2% for EnV, p < 0.001, or neurological deficits 44.7% versus 3.9% for EnV, p < 0.001. CSF neutrophils were lower in HSV (median 3.0% versus 9.5%, p = 0.0002); median lymphocytes (87.0% versus 67.0%, p = 0.0004) and protein (0.9 g/L versus 0.6 g/L, p = 0.0005) were elevated. Conclusion. Our study found that HSV patients were older and more likely to have seizure, altered mental status, or neurological deficits than patients with benign EnV meningitis. HSV cases had lower CSF neutrophils, higher lymphocytes, and higher protein levels.

Virological testing of cerebrospinal fluid in children aged less than 14 years with a suspected central nervous system infection: A retrospective study on 304 consecutive children from January 2012 to May 2015

OBJECTIVE

The study aimed to describe the prevalence of HSV DNA, VZV DNA, Enterovirus RNA, Parechovirus RNA, CMV DNA, EBV DNA, adenovirus DNA, HHV-6 DNA, HHV-7 DNA, HHV-8 DNA and Parvovirus B19DNA in children aged less 14 years with a suspected viral infection of the central nervous system in a clinical practice setting.

METHODS

Between January 2012 and May 2015, cerebrospinal fluids from 304 children were tested with an in-house real-time PCR method.

RESULTS

A positive PCR was detected in 64 subjects (21%): the mean number of tests performed in patients who showed a viral infection was 7.5, significantly higher (p = 0.001) with respect to that reported in negative samples (6.4). Enterovirus is the leading virus detected: 12 out of the 37 positive children reported were newborns (85.7% of all the newborns with a positive result). The second most frequently identified virus was HHV-7 (5 positive PCR out of 105 samples tested, 4.8%, if we excluded a child with a concomitant S. pneumoniae isolated), a prevalence significantly higher with respect to VZV (p = 0.02) and to CMV (p = 0.04). HHV-6 was the third most commonly identified aetiology (4.2%). All children were immunocompetent.

SIGNIFICANCE

Only a minority of children had a specific viral aetiology identified: the rate of HHV-7 positivity suggests a routine testing of these viruses within the diagnostic algorithm in immunocompetent paediatric patients. This approach could help to define the clinical role of this herpesvirus.

Criteria for reducing unnecessary testing for herpes simplex virus, varicella-zoster virus, cytomegalovirus, and enterovirus in cerebrospinal fluid samples from adults

Excessive utilization of laboratory diagnostic testing leads to increased health care costs. We evaluated criteria to reduce unnecessary nucleic acid amplification testing (NAAT) for viral pathogens in cerebrospinal fluid (CSF) samples from adults. This is a single-center split retrospective observational study with a screening cohort from 2008 to 2012 and a validation cohort from 2013. Adults with available results for herpes simplex virus 1/2 (HSV-1/2), varicella-zoster virus (VZV), cytomegalovirus (CMV), or enterovirus (EV) NAAT with CSF samples between 2008 and 2013 were included (n = 10,917). During this study, 1.3% (n = 140) of viral NAAT studies yielded positive results. The acceptance criteria of >10 nucleated cells/μl in the CSF of immunocompetent subjects would have reduced HSV-1/2, VZV, CMV, and EV testing by 63%, 50%, 44%, and 51%, respectively, from 2008 to 2012. When these criteria were applied to the 2013 validation data set, 54% of HSV-1/2, 57% of VZV, 35% of CMV, and 56% of EV tests would have been cancelled. No clinically significant positive tests would have been cancelled in 2013 with this approach. The introduction of a computerized order entry set was associated with increased test requests, suggesting that computerized order sets may contribute to unnecessary testing. Acceptance criteria of >10 nucleated cells/μl in the CSF of immunocompetent adults for viral CSF NAAT assays would increase clinical specificity and preserve sensitivity, resulting in significant cost savings. Implementation of these acceptance criteria led to a 46% reduction in testing during a limited follow-up period.

Detection and differentiation of herpes simplex viruses by use of the viper platform: advantages, limitations, and concerns

The Viper HSV-Q(x) assay was evaluated for the detection of herpes simplex virus 1 (HSV-1) and HSV-2 in specimens from oral, anogenital, and other miscellaneous sites. The HSV-Q(x) assay was found to be highly sensitive and accurate; however, a gray zone may be required for specimens with values falling between 50 and 800 maximum relative fluorescence units.

Light microscopy, culture, molecular, and serologic methods for detection of herpes simplex virus

Herpes simplex virus 1 (HSV-1) and 2 (HSV-2) cause a variety of human diseases, ranging from acute to chronic and mild to severe. The absence of curative therapy results in lifelong carriage marked by recurrent outbreaks and allows transmission of the virus to uninfected individuals. Nonspecific lesions, variable presentation, and chronic carriage necessitate the use of different laboratory testing methods appropriate for each presentation. A thorough understanding of the performance characteristics and limitations of available tests is critical for selection of the appropriate test and interpretation of results. Clinical sensitivity, specificity, and selection of the appropriate methodology is paramount to avoid misdiagnosis and guide therapy. In this article we review the different methods for detection and typing of HSV, including light microscopy, culture, serology, and nucleic acid-based tests. We discuss the strengths and weaknesses of each method for diagnosing HSV infection, cite performance characteristics, and review appropriate clinical uses.

Development of recombinant antigen array for simultaneous detection of viral antibodies

Protein microarrays have been developed to study antibody reactivity against a large number of antigens, demonstrating extensive perspective for clinical application. We developed a viral antigen array by spotting four recombinant antigens and synthetic peptide, including glycoprotein G of herpes simplex virus (HSV) type 1 and 2, phosphoprotein 150 of cytomegalovirus (CMV), Rubella virus (RV) core plus glycoprotein E1 and E2 as well as a E1 peptide with the optimal concentrations on activated glass slides to simultaneously detect IgG and IgM against HSV1, HSV2, CMV and RV in clinical specimens of sera and cerebrospinal fluids (CSFs). The positive reference sera were initially used to measure the sensitivity and specificity of the array with the optimal conditions. Then clinical specimens of 144 sera and 93 CSFs were tested for IgG and IgM antibodies directed against HSV1, HSV2, CMV and RV by the antigen array. Specificity of the antigen array for viral antibodies detection was satisfying compared to commercial ELISA kits but sensitivity of the array varied relying on quality and antigenic epitopes of the spotting antigens. In short, the recombinant antigen array has potential to simultaneous detect multiple viral antibodies using minute amount (3 µl) of samples, which holds the particularly advantage to detect viral antibodies in clinical CSFs being suspicious of neonatal meningitis and encephalitis.

PCR for detection of herpes simplex virus in cerebrospinal fluid: alternative acceptance criteria for diagnostic workup

The determination of herpes simplex virus (HSV) infection using a PCR assay is one of the most commonly requested tests for analysis of cerebrospinal fluid (CSF), although only a very low proportion of results are positive. A previously reported study showed that selecting only those CSF samples with >5 leukocytes/mm(3) or a protein level of >50 mg/dl was adequate for the diagnostic workup. The aim of the present study was to assess the reliability of alternative acceptance criteria based on elevated CSF white blood cell counts (>10 cells/mm(3)). We analyzed all requests for HSV PCR received between January 2008 and December 2011. CSF samples were accepted for analysis if they had >10 cells/mm(3) or if the sample was from an immunocompromised patient or a child aged <2 years. In order to evaluate our selection criteria, we identified those CSF samples with a leukocyte count of 5 to 10 cells/mm(3) or protein levels of >50 mg/dl in order to test them for HSV type 1 and 2 (HSV-1 and HSV-2) DNA. During the study period, 466 CSF samples were submitted to the microbiology laboratory for HSV PCR. Of these, 268 (57.5%) were rejected, and 198 (42.5%) were tested according to our routine criteria. Of the tested samples, 11 (5.5%) were positive for HSV DNA (7 for HSV-1 and 4 for HSV-2). Of the 268 rejected specimens, 74 met the criteria of >5 cells/mm(3) and/or protein levels of >50 mg/dl. Of these, 70 (94.6%) were available for analysis. None of the samples yielded a positive HSV PCR result. Acceptance criteria based on CSF leukocyte counts, host immune status, and age can help to streamline the application of HSV PCR without reducing sensitivity.

Laboratory diagnosis of CNS infections by molecular amplification techniques

The initial presentation of symptoms and clinical manifestations of CNS infectious diseases often makes a specific diagnosis difficult and uncertain, and the emergence of polymerase chain reaction-led molecular techniques have been used in improving organism-specific diagnosis. These techniques have not only provided rapid, non-invasive detection of microorganisms causing CNS infections, but also demonstrated several neurologic disorders linked to infectious pathogens. Molecular methods performed on cerebrospinal fluid are recognized as the new 'gold standard' for some of these infections caused by microorganisms that are difficult to detect and identify. Although molecular techniques are predicted to be widely used in diagnosing and monitoring CNS infections, the limitations as well as strengths of these techniques must be clearly understood by both clinicians and laboratory personnel.

An unusual presentation of herpes simplex virus encephalitis

We present a case of a 65-year-old man with an acute alteration in mental state that was initially diagnosed as a functional psychiatric condition. After extensive workup, herpes simplex virus type 1 (HSV-1) was detected in the patient's cerebrospinal fluid (CSF) by polymerase chain reaction (PCR), and he responded rapidly to treatment with acyclovir. The case illustrates the importance of actively excluding organic causes in such patients, the need to have a low threshold of suspicion for HSV encephalitis, and the central role of CSF PCR testing for the diagnosis of HSV encephalitis, even in the absence of CSF biochemical abnormalities.

Fatal herpes virus type I infection in a newborn

The authors present a case of environmentally acquired fatal herpes virus type I infection in a newborn after cesarean section and a discussion of the clinical presentation, pathogenesis and diagnosis of herpes simplex type I (HSV-1) at autopsy. Herpes simplex virus, both type I and type II, are well described infectious agents in newborns. Though herpes simplex type II (HSV-2) is commonly associated with fatal neonatal infections, it is important to consider HSV-1 to make the correct diagnosis. Additionally, although HSV infections are typically acquired during parturition, it is possible to be infected postpartum from the environment as occurred in this case. The diagnosis of neonatal HSV must also be communicated by the forensic pathologist to applicable healthcare providers and health care facilities, because of public health and medicolegal issues.

Serological microarray for detection of HSV-1, HSV-2, VZV, and CMV antibodies

The seroprevalence of human herpesviruses is high and reactivations occur frequently. A microarray was designed and tested for the detection of IgG and IgM antibodies for Puumala hantavirus (PUUV) and IgG antibodies against four herpesviruses. Initially, a microarray platform was set up using an unrelated in-house antigen, PUUV recombinant nucleocapsid protein, to optimize the protocol for the detection of antibodies. Detection of the four herpesviruses was set up in a microarray using the recombinant proteins of herpes simplex virus (HSV) glycoprotein G1 and G2, varicella-zoster virus (VZV) glycoprotein E, and cytomegalovirus (CMV) pp150 phosphoprotein. The results of the PUUV panel were in good agreement with the PUUV IgG immunofluorescent assay and IgM enzyme immunoassay (EIA). Seropositive and negative clinical reference panels were tested for herpesviruses by the serological microarray, and the results were compared to those of individual EIAs used for standard diagnostic purposes. The serologic microarray for HSV, VZV and CMV antibody detection gave good specificities for IgG. However, sensitivities of the assay varied depending on the herpesvirus detected. The serological microarray showed potential for screening purposes. The microarray based analyses were easy to perform, and HSV-1, HSV-2, VZV, and CMV antibodies could be detected on the same microarray.

Clinical validation of a new triplex real-time polymerase chain reaction assay for the detection and discrimination of Herpes simplex virus types 1 and 2

A new triplex real-time polymerase chain reaction (PCR) assay for Herpes simplex virus (HSV) (artus HSV-1/2 TM PCR kit, QIAGEN) was evaluated. This assay simultaneously uses three differently labeled probes targeted to HSV-1 (FAM), HSV-2 (NED), and to the manufacturer's Internal Control (VIC). HSV-1/2 typing capability and quantitation accuracy were determined using HSV stocks and quality control panels. Performance in routine clinical testing was compared with a nested HSV-1/2 PCR assay. Dilution series and quality control panel testing revealed an approximately 10-fold higher HSV-2 sensitivity in real-time PCR compared with an in-house nested PCR assay. The sensitivity for HSV-1 was comparable in both assays. All HSV-positive proficiency panel samples (n = 21) and virus stocks were typed correctly as HSV-1 or HSV-2 using real-time PCR. Quantitation correlated well with reference values (HSV-1, r = 0.98; HSV-2, r = 0.88), and 95% detection limits were determined as 9.4 HSV-2 copies/reaction and 18 HSV-1 copies/reaction. Based on C(t) values, the mean intra-assay coefficient of variation was 1%, whereas the interassay coefficient of variations were 2.7% and 2.5% for HSV-1 and -2, respectively. Testing of 309 clinical samples resulted in 100% specificity and 97% sensitivity. In conclusion, the artus HSV-1/2 TM PCR kit represents an excellent tool for the detection and differentiation of HSV-1 and -2 in clinical samples.

Herpes simplex virus type 2 displays atypical melting-temperature profiles at low viral titers

Real-time PCR is a powerful tool for the detection and typing of herpes simplex virus (HSV). HSV types 1 and 2 can be distinguished by using the differences in the melting temperatures (T(m)s) of the hybridization probes. The efficacy of T(m) profiling with low DNA concentrations was evaluated in this study.