TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: BORDG    
Bordetella pertussis Antibody, IgG, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of recent infection with Bordetella pertussis in patients with symptoms consistent with whooping cough for 2 or more weeks

 

This test should not be used as a test of cure, to monitor response to treatment, or to determine vaccine status.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Bordetella pertussis, the causative agent of whooping cough, is highly contagious and remains endemic in the United States despite the high rate of vaccination. Acute B pertussis infections are typically diagnosed by culture or nucleic acid amplification testing (NAAT). However, symptomatic adults and adolescents often seek medical attention later in the course of infection at which time the sensitivity of these 2 methods to detect the infectious agent decreases. A serologic response to B pertussis is typically mounted 2 weeks following infection and, therefore, detection of IgG-class antibodies to pertussis toxin (PT), which is only produced by B pertussis, can be a useful adjunct for diagnosis at later stages of illness.

 

Prior to testing, providers should review whether the patient was recently vaccinated using the Tdap (Tetanus-Diphtheria-acellular Pertussis) or DTap vaccines. The acellular pertussis vaccine contains 1 to 5 B pertussis antigens, including filamentous hemagglutinin, pertactin, 2 fimbrial agglutinogens, and significant levels of PT. Therefore, recent vaccination for B pertussis, specifically within the last 2 to 6 months, may lead to a positive result by the anti-PT IgG assay, and knowledge of the patient's vaccination history is important for accurate result interpretation.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

> or =100 IU/mL (positive)

> or = 40-<100 IU/mL (borderline)

<40 IU/mL (negative)

Reference values apply to all ages.

Interpretation Provides information to assist in interpretation of the test results

Negative (<40 IU/mL): No IgG antibodies to pertussis toxin (PT) detected. Results may be falsely negative in patients with less than 2 weeks of symptoms.

 

Borderline (40-<100 IU/mL): Recommend follow-up testing in 10 to 14 days if clinically indicated.

 

Positive (> or =100 IU/mL): IgG antibodies to pertussis toxin (PT) detected. Results suggest recent infection with or recent vaccination against Bordetella pertussis.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test should not be used in neonates, young infants or in children between the ages of 4 to 7 years as the routine childhood vaccine schedule may interfere with result interpretation.

 

Immune response following vaccination cannot be distinguished from recent infection.

 

For diagnosis, clinical symptoms, the patient's age and vaccination history should always be taken into account along with the serological results.

 

Whooping cough caused by Bordetella parapertussis will not be detected by this assay.

 

The CDC recommends nucleic acid amplification tests (NAAT) or culture as first-line tests for B pertussis infection. However, serologic testing may be useful in patients who are symptomatic for more than 2 weeks.

Supportive Data

Accuracy:

A total of 108 previously characterized serum samples (originally tested by Focus Diagnostics Inc.) were evaluated by the EuroImmun antipertussis toxin (PT) IgG EIA and the results are indicated below.

 

Comparison of the EuroImmun and Focus Diagnostics Bordetella pertussis PT EIAs

                       

Focus Diagnostics PT EIA

Positive

Negative

EuroImmun PT EIA

Positive

18

0

Negative

0

77

Borderline(a)

8(b)

5(c)

 

 

 

 

 

 

 

 

 

(a)Testing of a convalescent sample is recommended. Samples not included in positive and negative agreement calculations below.

(b) All 8 samples had low positive values by the Focus assay.

(c) All 5 samples were near the lower end of the borderline range for the EuroImmun ELISA.

 

Positive Agreement: 100% (18/18); 95% Confidence Interval (CI): 79.3%-100%

Negative Agreement: 100% (77/77); 95% CI: 94.3%-100%

Overall Agreement: 95.4% (95/108); 95% CI: 80.4%-93.0%

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Leber AL: Pertussis: relevant species and diagnostic update. Clin Lab Med 2014;34:237-255

2. Guiso N, Berbers G, Fry NK, et al: What to do and what not to do in serological diagnosis of pertussis: recommendation from EU reference laboratories. Eur J Clin Microbiolo Infect Dis 2011;30(3):307-312

3. Andre P, Caro V, Njamkepo E, et al: Comparison of serological and real-time PCR assays to diagnose Bordetella pertussis infection in 2007. J Clin Microbiol 2008;46(5):1672-1677