Evaluation of a novel dry latex preparation for demonstration of infectious mononucleosis heterophile antibody in comparison with three established tests

Validity of a point-of-care based on heterophile antibody detection for the diagnosis of infectious mononucleosis in primary care

OBJECTIVE

To evaluate the validity of a point-of-care test to diagnose infectious mononucleosis (IM) compared with Epstein-Barr virus (EBV) specific serology.

METHODS

Patients over 14 years with sore throat and four Centor criteria--tonsillar exudate, fever, lymph glands tenderness and absence of cough--and negative pharyngeal testing for group A β-haemolytic streptococcal antigen were consecutively recruited. All patients underwent pharyngotonsillar swab for microbiological culture, the rapid OSOM MonoTest for the diagnosis of IM in whole blood, the Paul-Bunnell test and complete blood analysis with serology for EBV and cytomegalovirus the day after the visit and at 15 days. Sensitivity and specificity were determined.

RESULTS

We included 145 patients with a mean age of 24 ± 6.8 years. Of these, serology was determined in 129 subjects, with IM being diagnosed in 14 (10.9%). Both the MonoTest and the Paul-Bunnell test were positive in 13 patients with IM (92.9%) with no patient without disease being positive for either test--sensitivity of 92.9% (95% CI: 64.2-99.6%) and specificity of 100% (95% CI: 96-100%). The culture showed streptococcus A infection in 1 case (0.7%) and streptococcus C in 62 cases (42.8%). A total of 78 patients presented past infection by EBV (60.5%).

CONCLUSIONS

Only one out of 10 patients with sore throat, four Centor criteria and negative rapid test for streptococcal infection presents IM. Despite the MonoTest presenting optimum sensitivity and specificity, it was found to have the same validity as the Paul-Bunnell test, with serological study continuing to be necessary for precise diagnosis of IM.

Revolutionizing clinical microbiology laboratory organization in hospitals with in situ point-of-care

BACKGROUND

Clinical microbiology may direct decisions regarding hospitalization, isolation and anti-infective therapy, but it is not effective at the time of early care. Point-of-care (POC) tests have been developed for this purpose.

METHODS AND FINDINGS

One pilot POC-lab was located close to the core laboratory and emergency ward to test the proof of concept. A second POC-lab was located inside the emergency ward of a distant hospital without a microbiology laboratory. Twenty-three molecular and immuno-detection tests, which were technically undemanding, were progressively implemented, with results obtained in less than four hours. From 2008 to 2010, 51,179 tests yielded 6,244 diagnoses. The second POC-lab detected contagious pathogens in 982 patients who benefited from targeted isolation measures, including those undertaken during the influenza outbreak. POC tests prevented unnecessary treatment of patients with non-streptococcal tonsillitis (n = 1,844) and pregnant women negative for Streptococcus agalactiae carriage (n = 763). The cerebrospinal fluid culture remained sterile in 50% of the 49 patients with bacterial meningitis, therefore antibiotic treatment was guided by the molecular tests performed in the POC-labs. With regard to enterovirus meningitis, the mean length-of-stay of infected patients over 15 years old significantly decreased from 2008 to 2010 compared with 2005 when the POC was not in place (1.43±1.09 versus 2.91±2.31 days; p = 0.0009). Altogether, patients who received POC tests were immediately discharged nearly thrice as often as patients who underwent a conventional diagnostic procedure.

CONCLUSIONS

The on-site POC-lab met physicians' needs and influenced the management of 8% of the patients that presented to emergency wards. This strategy might represent a major evolution of decision-making regarding the management of infectious diseases and patient care.

Mucocutaneous manifestations of Epstein-Barr virus infection

This review focuses on Epstein-Barr virus (EBV) infection, diagnosis, and current treatment, with emphasis on EBV-associated mucocutaneous manifestations in primary infections, acute EBV-associated syndromes, chronic infections, lymphoproliferative disorders, and lymphomas. In primary infection, EBV infects B cells and can cause mucocutaneous manifestations in infectious mononucleosis or acute EBV-associated syndromes such as Gianotti-Crosti syndrome and hemophagocytic syndrome. EBV then persists in the majority of humans generally without causing disease. In some cases, however, latent EBV infection may result in diseases such as hydroa vacciniforme, hypersensitivity to mosquito bites, and lymphoproliferative disorders such as plasmablastic lymphoma, oral hairy leukoplakia, and post-transplant lymphoproliferative disorders, particularly in immunocompromised patients. Latent EBV infection has also been implicated in a variety of malignant conditions such as Burkitt lymphoma, Hodgkin lymphoma, nasopharyngeal carcinoma, and Kikuchi histocytic necrotizing lymphadenitis. Since the immune system is critical in preventing the progression of EBV disease, the immunologic status of the patient plays a crucial role in the subsequent development of pathologies.

Real-time Epstein-Barr virus PCR for the diagnosis of primary EBV infections and EBV reactivation

BACKGROUND

The serological diagnosis of primary Epstein-Barr virus (EBV) infections is often difficult, whereas the relevance of elevated immunoglobulin G (IgG) antibodies against early antigen (EA) for the diagnosis of EBV reactivation has increasingly become a matter of dispute. Recently, EBV PCR has been added as a diagnostic tool. Positive EBV PCR has been demonstrated in the serum of patients with primary EBV infections and EBV reactivation.

OBJECTIVES

To compare classical serological diagnosis of primary EBV infection and EBV reactivation with real-time EBV PCR.

STUDY DESIGN

Sera from 45 patients were selected with detectable immunoglobulin M (IgM) antibodies against EBV viral capsid antigen (VCA), and 62 sera were selected with a reactivation profile. A real-time EBV PCR was performed with DNA extracted from these sera.

RESULTS

Based on serological data, the diagnosis of primary EBV infection was established for 24 of the 45 IgM VCA-positive patients. By performing PCR, seven extra cases of primary infection were diagnosed for which no heterophilic antibodies could be detected. In five cases of primary infection, no EBV DNA could be detected by PCR. Only in two of the 62 sera with a reactivation seroprofile could EBV DNA be detected.

CONCLUSIONS

Based on these data, we suggest that for the diagnosis of primary infections, EBV PCR could lead to an increase of >16% in the number of positive diagnoses by confirming a positive IgM VCA in the absence of heterophilic antibodies. Furthermore, EBV PCR is positive in only 3% of sera with elevated antibodies against EA, raising doubt as to the utility of EA titers for diagnosing EBV reactivation.

Real-time Epstein-Barr virus PCR for the diagnosis of primary EBV infections and EBV reactivation

BACKGROUND

The serological diagnosis of primary Epstein-Barr virus (EBV) infections is often difficult, whereas the relevance of elevated immunoglobulin G (IgG) antibodies against early antigen (EA) for the diagnosis of EBV reactivation has increasingly become a matter of dispute. Recently, EBV PCR has been added as a diagnostic tool. Positive EBV PCR has been demonstrated in the serum of patients with primary EBV infections and EBV reactivation.

OBJECTIVES

To compare classical serological diagnosis of primary EBV infection and EBV reactivation with real-time EBV PCR.

STUDY DESIGN

Sera from 45 patients were selected with detectable immunoglobulin M (IgM) antibodies against EBV viral capsid antigen (VCA), and 62 sera were selected with a reactivation profile. A real-time EBV PCR was performed with DNA extracted from these sera.

RESULTS

Based on serological data, the diagnosis of primary EBV infection was established for 24 of the 45 IgM VCA-positive patients. By performing PCR, seven extra cases of primary infection were diagnosed for which no heterophilic antibodies could be detected. In five cases of primary infection, no EBV DNA could be detected by PCR. Only in two of the 62 sera with a reactivation seroprofile could EBV DNA be detected.

CONCLUSIONS

Based on these data, we suggest that for the diagnosis of primary infections, EBV PCR could lead to an increase of >16% in the number of positive diagnoses by confirming a positive IgM VCA in the absence of heterophilic antibodies. Furthermore, EBV PCR is positive in only 3% of sera with elevated antibodies against EA, raising doubt as to the utility of EA titers for diagnosing EBV reactivation.