Among these 14 894 adults, 265 adults (107 men and 158 women; 1.2%) aged 23.9 to 95.4 years (median: 68.8 years) had macrocytic anemia, showing Hb findings below the lower limit of the reference interval for each sex and gender and MCV results of greater than 102 fL, from among 94 local clinics or hospitals without in‐house clinical laboratories in Korea. The gene discussed is GSTM1; the disease is macrocytic anemia.