Evaluation of a bedside immunotest to predict individual anti-tetanus seroprotection: a prospective concordance study of 1018 adults in an emergency department.
BACKGROUND
Unscheduled tetanus prophylaxis (UTP) used in the emergency room (ER) in patients with wounds who are unaware of their vaccination history is erroneous in 40% of cases. Evaluation of bedside tetanus immunity with the Tétanos Quick Stick (TQS) test may improve UTP.


OBJECTIVE
To show that (1) a positive TQS result reflects immunity to tetanus; and (2) TQS is reproducible by ER workers.


METHODS
In a prospective concordance study, immunity to tetanus of patients with wounds was assessed by two techniques: (1) TQS at the bedside, which detects specific tetanus antitoxins at concentrations > or =0.2 IU/ml in whole blood or > or =0.1 IU/ml in serum; (2) ELISA in the laboratory (threshold >0.1 IU/ml). The study comprised three groups: (A) healthcare personnel self-tested with the two techniques to determine the effect of training; (B) selected patients with wounds were double-tested with TQS by two healthcare providers whose readings were compared to test reproducibility; and (C) all patients with wounds aged > or =15 years were consecutively included.


RESULTS
Of 1018 individuals included, 60 were in group A, 50 were in group B and 908 were in group C. 403 patients who were not included were similar to those included for age, vaccination history and types of wounds. The reproducibility of the test was 98%. TQS sensitivity was 83.0%, specificity 97.5%, positive predictive value 99.6% and negative predictive value 42.9%.


CONCLUSIONS
TQS reliably predicts tetanus immunity and is reproducible by healthcare providers. Although it may not accurately discriminate between patients with ongoing and declining immunity, it is currently the most sensitive and specific tool for guiding tetanus prophylaxis and should be included in current guidelines on UTP.
Elkharrat
D
D
Service des Urgences Médico-chirurgicales, Hôpital Ambroise Paré, 9 avenue Charles de Gaulle, 92 100 Boulogne-Billancourt, France. david.elkharrat@apr.aphp.fr
Sanson-Le-Pors
M-J
MJ
Arrouy
L
L
Beauchet
A
A
Benhamou
F
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004636:Emergency Service, Hospital; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007159:Immunologic Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D011795:Surveys and Questionnaires; D013742:Tetanus / Q000276:immunology*; D013743:Tetanus Antitoxin / Q000276:immunology* / Q000627:therapeutic use; D055815:Young Adult
D013743:Tetanus Antitoxin