The correlation of serum carbohydrate antigen 19-9 with benign hydronephrosis.

Purpose: High serum carbohydrate antigen 19-9 in patients with hydronephrosis but without malignant disease is reportedly rare but to our knowledge the clinical features of hydronephrosis that affect this level have not yet been clarified. We examined the correlation of serum carbohydrate antigen 19-9 with hydronephrosis status in patients with benign hydronephrosis.

Materials And Methods: We used 123 serum samples from 68 patients with and 55 without hydronephrosis. All patients enrolled in this study had no malignant disease. Serum carbohydrate antigen 19-9 was measured by immunoradiometric assay and that level was correlated with clinical factors.

Results: Serum carbohydrate antigen 19-9 in patients with hydronephrosis was significantly higher than in those without hydronephrosis (p <0.0001). The serum level was elevated to greater than 37 units per ml. in 25% of the patients with but in only 1.8% of those without hydronephrosis. In the hydronephrosis group the clinical features that significantly correlated with the increased serum level were bilateral hydronephrosis, urinary tract infection, proteinuria, increased serum blood urea nitrogen, severe urinary tract occlusion and high grade hydronephrosis.

Conclusions: Serum carbohydrate antigen 19-9 was significantly elevated in patients with benign hydronephrosis. Hydronephrosis causes false-positive results when screening for malignant disease by serum carbohydrate antigen 19-9 measurement.