ABSTRACT
Objectives: To evaluate the significance of serum chromogranin A [CgA] status in patients with and without different neuroendocrine tumors [NETs] by conducting a retrospective assessment of the diagnostic utility and limitations of CgA as a biomarker for NETs in a tertiary care hospital in Oman
Methods: We conducted a retrospective analysis of CgA requests referred to the Clinical Biochemistry Laboratory, Royal Hospital, Oman over a 24-month period [April 2012 to March 2014]. During this time, 302 CgA tests for 270 patients [119 males and 151 females; age range 11-86 years and mean+/-standard deviation [SD] 44.0+/-18.0 years], were requested. Of these CgA tests, 245 tests were performed for 245 patients investigated for the diagnosis of NETs, and 57 CgA tests were performed for 25 patients with diagnosed NETs who were undergoing follow-up. Serum CgA levels were analyzed using the enzyme-linked immunosorbent assay based on a cut-off value of 22 IU/L
Results: Of the 302 CgA tests reviewed, 197 [65.2%] were within the quoted normal range; however, 105 [34.8%] had CgA > 22 IU/L. Of the 245 patients with first-line CgA, 38 patients [15.5%] had NET that included carcinoid, pheochromocytoma, pancreatic NET, adrenal adenoma, prostatic adenocarcinoma, gastrointestinal NET, medullary thyroid carcinoma, Schwannoma, lung small cell carcinoma, parathyroid adenoma, and pituitary macroadenoma. The mean+/-SD of CgA in these patients with NETs was 205.0+/-172.0 IU/L. Meanwhile, there were 45 [18.3%] patients with CgA > 22 IU/L [83.0+/-116.0 IU/L] who did not have NETs. The conditions/diseases included: essential hypertension, chronic kidney disease, heart failure, peptic ulcer, chronic diarrhea, use of proton pump inhibitors, and other chronic diseases [hypothyroidism, asthma, diabetes mellitus]. Of the 25 patients with known NET who were followed-up, there were 57 CgA results [29 with CgA 22 IU/L]. The overall clinical sensitivity of CgA in the diagnosis of NETs was 84.2%, overall specificity was 78.2%, positive predictive value was 41.5%, negative predictive value was 96.4%, and overall efficiency was 79.2%. In patients with individual NET, a good reflection in CgA was noticed in the follow-up period following surgery or therapy
Conclusions: Serum CgA is a sensitive and effective noninvasive laboratory test for the clinical detection and management of NETs. Awareness of the pitfalls of the tests in patients with non-NET conditions, particularly chronic diseases and use of certain drugs, is important to be considered during the interpretation of the CgA levels
ABSTRACT
There are technical limitations for the currently available methods of measuring serum total and free testosterone in females. The study objectives were to evaluate the usefulness of serum total testosterone, sex hormone-binding globulin [SHBG], free androgen index [FAI], and calculated free testosterone [CFT] in the assessment of androgen status in women investigated for suspected hyperandrogenism. This is a case control study that was conducted during the period from 1[st] May 2011 to 31[st] October 2011 on 122 patients aged [18-45 years] whom were referred to the Clinical Biochemistry Laboratory from the Endocrinology and Gynecology Clinics, Royal Hospital, Oman. Women with no clinical feature or laboratory data indicative of hormonal dysfunction and with midluteal progesterone >30 nmol/L were selected as controls [group 1; n=18]. The patients were divided into subgroups based on the clinical/laboratory diagnosis of polycystic ovary syndrome [PCOS [group 2; n=19], hirsutism [group 3; n=18], menstrual disturbances [irregularities] or infertility [group 4; n=49], as well as combination of PCOS or hirsutism and menstrual disturbances or infertility [group 5;n=18]. Serum total testosterone and SHBG were measured, FAI was calculated as percentage ratio of total testosterone to SHBG values, and CFT was calculated according to Vermeulen equation. There was a statistically significant difference in the mean levels of testosterone, FAI and CFT in each patient group compared with the control group. For diagnosing hyperandrogenism, each indicator was selected at the recommended cut-off: testosterone >3.0 nmol/L, SHBG <30 nmol/L, FAI >5%, and CFT >32 pmol/L. In group 2, 89.5% and 94.7% of the patients had increased FAI and CFT, respectively; compared with 36.4% for increased testosterone. In group 3, 88.9% and 88.9% of the patients had similarly increased FAI and CFT, respectively; compared with 66.7% for testosterone. In group 4, patients had 63.3% and 73.5% elevated FAI and CFT, respectively; compared with 53.1% for testosterone, while in group 5, patients had 83.3% and 88.9% elevated FAI and CFT, respectively, compared with 61.1% for testosterone. The diagnosis of hyperandrogenism was most obvious when using CFT or FAI than testosterone alone. It is thus recommended to include these calculated parameters [CFT and/or FAI] in the routine investigation and assessment of women with disorders related to clinical or biochemical hyperandrogenism