Elevation of serum CA 19-9 in parallel with HbA1c in a diabetic female with the Lewis(a+b-) blood group.

We report a 66-yr-old diabetic female with her serum CA 19-9 levels elevated in parallel with her hemoglobin A1c (HbA1c) levels. She was initially suspected of having pancreatic cancer, but this was later proved to be false. Her serum CA 19-9 levels varied between 58 and 235 U/ml over a 3-yr period, and correlated significantly (r = 0.68, P less than 0.01) with her HbA1c levels (7.2-13.3%). She belonged to the Lewis (a+b-) blood group. Serum CA 19-9 levels were also assessed in 73 diabetic patients (36 males and 37 females) in relation to sex and Lewis blood group. The mean level of serum CA 19-9 was higher in females than in males in each Lewis blood group, and it was the highest in patients with Le(a+b-) and the lowest in Le(a-b-). Patients with a higher level of HbA1c showed a higher level of serum CA 19-9 in Le(a+b-), but patients with Le(a-b-) showed a low level of serum CA 19-9 irrespective of HbA1c level. Patients with Le(a-b+) appeared to intermediate between the patients with Le(a+b-) Le(a-b-). Thus, the elevation of serum CA 19-9 level due to hyperglycemia was indicated to be affected by sex as well as Lewis blood group. The biosynthesis of CA 19-9 seemed to be accelerated in hyperglycemic diabetic patients, especially in females. Consequently, it was considered that the present case was a diabetic female with the Le(a + b -) blood group, which led to showing a relatively high level of serum CA 19-9 correlated with HbA1c level.