Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (891 page)

   Disseminated cancer and monoclonal gammopathies

   Pregnancy

   Major injury and surgery

   Increasing age

   Inflammatory conditions

   Limitations

   The ultrasensitive
D
-dimer may be falsely elevated or decreased in hyperlipidemic or very turbid blood samples and in patients treated with mouse monoclonal antibodies.

   RF may give false-positive results.

DEHYDROEPIANDROSTERONE SULFATE, SERUM (DHEA-SULFATE)

   Definition

   DHEA-S is produced by androgenic zone of the adrenal cortex. DHEA is the principal human C-19 steroid and has very low androgenic potency but serves as the major direct or indirect precursor for most sex steroids. The bulk of DHEA is secreted as a 3-sulfoconjugate (DHEA-S). Both hormones are albumin bound, but binding of DHEA-S is much tighter. In gonads and several other tissues, most notably skin, steroid sulfatases can convert DHEA-S back to DHEA, which can then be metabolized to stronger androgens and to estrogens. During pregnancy, DHEA-S and its 16-hydroxylated metabolites are secreted by the fetal adrenal gland in large quantities. They serve as precursors for placental production of the dominant pregnancy estrogen, estriol.

   
Normal range:
see Table 16.28.

TABLE 16–28. Normal Ranges of DHES-S

   Use