The measurement of urinary beta core fragment in conjunction with serum CA125 does not aid the differentiation of malignant from benign pelvic masses.

The urinary concentration of the renal metabolite of the beta subunit of human chorionic gonadotropin (beta core) has been proposed as a tumor marker in certain nontrophoblastic malignancies including those of the female genital tract. A previous study investigated the use of urinary beta core in conjunction with serum CA125 in distinguishing malignant from benign pelvic masses and showed that the combined test improved the overall sensitivity to 88%; this was greater than that for either test alone. However, the cutoff levels used to distinguish normal from abnormal were approximately six times greater than those generally used for CA125 and four to five times lower than those used for beta core in our laboratory. Furthermore there was no recognition of the possible difference in normal levels of beta core between pre- and postmenopausal women. We have examined a similar group of cases using our cutoff levels for urinary beta core of 0.36 ng/ml in premenopausal women and 0.48 ng/ml in postmenopausal women and 35 u/ml for CA125. We show that measurement of CA125 is substantially more sensitive that that of beta core and that the combination of beta core with CA125 does not improve the overall sensitivity of the test. However, there was a small improvement in positive predictive value if both tests were positive (97.5%) and of specificity when one or the other test was negative (98.5%).