Lymphogranuloma venereum laboratory findings

Lymphogranuloma venereum Microchapters
Home
Patient Information
Overview
Historical Perspective
Pathophysiology
Causes
Classification
Differentiating Lymphogranuloma venereum from other Diseases
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Lymphogranuloma venereum laboratory findings On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Lymphogranuloma venereum laboratory findings All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Lymphogranuloma venereum laboratory findings
CDC on Lymphogranuloma venereum laboratory findings
Lymphogranuloma venereum laboratory findings in the news
Blogs on Lymphogranuloma venereum laboratory findings
Directions to Hospitals Treating Lymphogranuloma venereum
Risk calculators and risk factors for Lymphogranuloma venereum laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nate Michalak, B.A.

Overview

Because of limitations in a commercially available test, diagnosis is primarily based on clinical findings. Direct identification of the bacteria from a lesion or site of the infection may be possible through testing for chlamydia but, this would not indicate if the chlamydia infection is LGV. However, the usual chlamydia tests that are available have not been FDA approved for testing rectal specimens. In a patient with rectal signs or symptoms suspicious for LGV, a health care provider can collect a specimen and send the sample to his/her state health department for referral to CDC, which is working with state and local health departments to test specimens and validate diagnostic methods for LGV.

Laboratory Findings

Culture

• Primary lesion swabs or bubo aspirate can be cultured on cyclohexamide-treated McCoy or HeLa cells.
• Sensitivity is approximately 75% - 85%.
• Culture is impractical due to its time-consuming nature, the fact that it's not readily available, and the test yields isolate only 30% of the time.

Serology

• Compliment fixation and immunofluorescence tests of lesion swab or bubo aspirate can be used to detect C. trachomatis.

• Serologic tests of rectal mucosa swabs from patients with proctitis are insensitive.

• Serology is only genus specific.
• Cross-reactivity with other species is possible.
• A complement fixation titer of >1:64 with appropriate clinical presentation is suggestive of LGV.
• An immunofluorescence titer of >1:256 with appropriate clinical presentation is suggestive of LGV.

Nucleic Acid Amplification Tests (NAATs)

• Lesion swabs, bubo aspirate, or rectal mucosa swabs can be tested for C. trachomatis using nucleic acid amplification tests (NAATs).
• NAATs have high specificity and sensitivity for C. trachomatis.
• NAATs performed on rectal specimens are not approved by the FDA but appear more accurate than other testing methods and are the preferred approach.

Polymerase Chain Reaction

• The diagnosis usually is made serologically (through complement fixation) and by exclusion of other causes of inguinal lymphadenopathy or genital ulcers. Serologic testing has a sensitivity of 80% after 2 weeks. Serologic testing may not be specific for serotype (has some cross reactivity with other chlamydia species) and can suggest LGV from other forms because of their difference in dilution, 1:64 more likely to be LGV and lower than 1:16 is likely to be other chlamydia forms. For identification of serotypes, culture is often used. Culture is difficult. Requiring a special media, cycloheximide-treated McCoy or HeLa cells, and yields are still only 30-50%.
• DFA, or direct fluorescent antibody test, PCR of likely infected areas and pus, are also sometimes used.
  • DFA test for the L-type serovar of C.trachomatis is the most sensitive and specific test, but is not readily available.
  • If polymerase chain reaction (PCR) tests on infected material are positive, subsequent restriction endonuclease pattern analysis of the amplified outer membrane protein A gene can be done to determine the genotype. Recently a fast real time PCR (Taqman analysis) has been developed to diagnose LGV. With this method an accurate diagnosis is feasible within a day. It has been noted that one type of testing may not be thorough enough.