Two cases of the same family with the unusual elevation of CA19-9 levels.

INTRODUCTION Serum carbohydrate associated antigen (CA19-9) is widely used marker in clinical practice and shows small increases in a few benign diseases. Here we report two cases, a mother and her daughter with slightly elevated CA19-9 levels not accompanied by any clinical pathology. CASE PRESENTATION The mother with elevated CA19-9 level (89.90 U/mL; upper limit of normal range (ULNR) < 37 U/mL) was referred to our department for evaluation. Similar increase was determined in her daughter incidentally. Daughter's CA19-9 level was 123.92 U/mL. Extensive laboratory data, imaging procedures and clinical evaluations were within the normal ranges except elevated CA19- 9 levels for both. Also, any pathology compatible with the elevated CA19-9 level couldn't be determined. In order to avoid laboratory errors and interferences, we measured the samples at four different immunoassay platforms twice. CONCLUSION Healthy people can be in excess of the ULNR. Therefore, clinicians need to be aware of these rare situations without missing the malignant disorders.