In the United States it is customary to perform close observation of the patient who had recent positive conversion of tuberculin skin test by repeated chest X-ray and even by treating with one of antituberculosis medications which may carry side effects to the patient and even to the fetus in the case of pregnant patient. These policies derive from the assumption that positive conversion of the skin test carries high probability of recent tuberculosis infection. These assumptions may not apply to the Japanese patient who came from Japan to this country. In Japan, tuberculin skin test administration was legally enforced first time at the age of less than four years of age. Negative responders were given BCG(bacille Calmette-Guerin). The same process was repeated when the child reaches to grade 1 and grade 2 of grammar school. And again, at grade 1 and grade 2 of junior high school. Because of this procedure, the majority of Japanese have normally positive skin test result long before they come to this country.
In view of the theoretical risk of malformation and increased incidence of leukemia by fetal radiation exposure, potential side effect of antituberculosis medication during pregnancy and further consideration of high incidence of positive skin test among Japanese population because of the above stated reasons, evaluation of positive skin test among pregnant Japanese population should be done with extreme caution to avoid any unnecessary radiation exposure and side effect of medication. I wish this information will be helpful in treating Japanese patient with positive tuberculin test.
Terusada Horiguchi, M.D.F.A.C.O.G.
JAPANESE MEDICAL SOCIETY OF AMERICA