What is the probability of false positive and false negative results from the serological tests?**

Vijay Kumar, M.D., Research Associate Professor at the University of Buffalo and President and Director of IMMCO Diagnostics: The three serological tests that are used for diagnosing celiac disease are:

• Anti-endomysial antibody (EMA)
• Anti-reticulin antibody (ARA)
• Anti-gliadin antibody (AGA)

Each of these three tests provide a certain degree of reliability for diagnosing celiac disease. Of these, endomysial antibody is the most specific test. The following table is taken from our studies (Lerner, Kumar, Iancu, Immunological diagnosis of childhood coeliac disease: comparison between antigliadin, antireticulin and antiendomysial antibodies).

Celiac.com Sponsor (A12):
 

The following definitions related to sensitivity, specificity, positive and negative predictive values may help:

Sensitivity is the probability of a positive test result in a patient with disease. Specificity is the probability of negative test result in a patient without disease. Positive predictive value is the probability of disease in a patient with positive test result. Negative predictive value is the probability of no disease in a patient with negative test result.

Karoly Horvath, M.D., Ph.D., Associate Professor of Pediatrics; Director, Peds GI & Nutrition Laboratory; University of Maryland at Baltimore: The summary below shows the results of the main serological tests based on several publications including 388 patients with celiac disease, and 771 healthy subjects.

SENSITIVITY- the proportion of subjects with the disease who have a positive test. It indicates how good a test is at identifying the diseased:

SPECIFICITY- the proportion of subjects without the disease who have a negative test. It indicates how good a test is at identifying the non-diseased:

POSITIVE PREDICTIVE VALUE- the probability that a person with positive results actually has the disease:

NEGATIVE PREDICTIVE VALUE- the probability that a person with negative results does not have the disease:

References:

McMillan SA, Haughton DJ, Biggart JD, Edgar JD, Porter KG, McNeill TA. Predictive value for coeliac disease of antibodies to gliadin, endomysium, and jejunum in patients attending for jejunal biopsy. Brit Med J 1991;303:1163-1165

Ferreira M, Lloyd Davies S, Butler M, Scott D, Clark M, Kumar P. Endomysial antibody: is it the best screening test for coeliac disease? Gut 1992;33:1633-1637.

Khoshoo V, Bhan MK, Puri S, Jain R, Jayashree S, Bhatnagar S, Kumar R, Stintzing G. Serum antigliadin antibody profile in childhood protracted diarrhea due to coeliac disease and other causes in a developing country. Scand J Gastroenterol 1989;24:1212-1216.

Chan KN, Phillips AD, Mirakian R, Walker-Smith JA. Endomysial antibody screening in children. J Pediatr Gastroenterol Nutr 1994;18:316-320.

Bode S, Weile B, Krasilnikoff PA, Gdmand-Hyer E. The diagnostic value of the gliadin antibody testing celiac disease in children: a prospective study. J Pediatr Gastroenterol Nutr 1993;17:260-264.

Calabuig M, Torregosa R, Polo P, Tom s C, Alvarez V, Garcia-Vila A, Brines J, Vilar P, Farr C, Varea V. Serological markers and celiac disease: a new diagnostic approach ? J Pediatr Gastroenterol Nutr 1990;10:435-442.