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Objectives Prostate cancer is the leading cancer in older men. The Ministry of Health Oman Cancer Incidence Registry 2013 lists cancer of the prostate as the first most common cancer in males. Therefore, early detection is important and prostate-specific antigen (PSA) is widely used as an established laboratory test. However, despite its wide use, its value in screening, particularly in asymptomatic males, is controversial when considering the risks and benefits of early detection. Methods This prospective, observational study included 136 males (67.0±8.9 years; range 45-90) who were scheduled for a prostate biopsy in two different tertiary care teaching hospitals in Oman: the Royal Hospital and Sultan Qaboos University Hospital. Blood specimens from these patients were collected at the same setting before obtaining a prostatic biopsy. Three PSA markers (total PSA (tPSA), free PSA (fPSA), and [-2]proPSA (p2PSA)) were measured and the Prostate Health Index (phi) calculated. The histopathological report of the prostatic biopsy for each patient was obtained from the histopathology laboratory of the concerned hospital along with clinical and laboratory data through the hospital information system. Results Phi has the highest validity markers compared with other prostate markers, with a sensitivity of 82.1%, specificity of 80.6%, and area under the curve (AUC) value of 0.81 at a cutoff of 41.9. The other prostatic markers showed sensitivities and specificities of 78.6% and 25.9% for tPSA; 35.7% and 92.6% for %fPSA; and 64.3% and 82.4% for %p2PSA, respectively. The AUCs at the best cutoff values were 0.67 at 10.1 µg/L for tPSA; 0.70 at 11.6% for %fPSA; and 0.55 at 1.4% for %p2PSA. An association between phi values and aggressiveness of prostate malignancy was noted. Of the 28 patients with prostate cancer, 22 patients had tPSA > 4 µg/L. However, no patient had phi in the low-risk category, and five, six, and 17 patients had phi in the moderate-, high-, and very high-risk categories, respectively. Conclusions Phi outperforms tPSA and fPSA when used alone or in combination, and appears to be more accurate than both markers in excluding prostate cancer before biopsy. Use of this biomarker helps clinicians to avoid unnecessary biopsies, particularly in patients with gray-zone tPSA level. Phi is the strongest marker that correlates proportionally with Gleason Score; therefore, it is also useful in predicting the aggressiveness of the disease. This is the first reported experience for the use of p2PSA and phi in Oman, the Middle East, and North Africa.

Pheochromocytoma is a rare tumor that typically originates in the adrenal glands, often causing the over-production of catecholamines. The aim of this study was to determine whether dietary status could affect the concentration of plasma-fractionated metanephrines. This study was conducted at the Chemical Pathology Laboratory, Royal Hospital, Oman. Three plasma samples were collected from each participant (16 male and 16 female) over three consecutive days (day one: dietary restriction,day two: excess intake of restricted foods, day three: random sample following the typical diet for each participant). Samples were collected and centrifuged to obtain the plasma, which was then stored at -20°C prior to analysis. Metanephrine and normetanephrine concentrations were measured by comparative ELISA. Plasma metanephrine and normetanephrine measured under the three different dietary conditions for each individual were not significantly different and within normal range. Pearson correlation coefficient analysis of plasma concentration of metanephrines within individual patients under the three dietary conditions revealed positive correlation. We found no significant effect of dietary status on plasma metanephrine or normetanephrine concentration. Therefore, samples taken under any dietary condition may be used to determine plasma MN and NMN concentration. However, dietary restrictions in the diagnosis of Pheochromocytoma need further investigations.

Objectives To evaluate the validity and compare the performance of cancer antigen-125 (CA-125), human epididymis protein 4 (HE4), the risk of malignancy index (RMI), and the risk of ovarian malignancy algorithm (ROMA) in the diagnosis of ovarian cancer in patients with ovarian lesions discovered during their preoperative work-up investigations. Methods This prospective, cross-sectional study looked at patients who attended the gynecology department at the Royal Hospital, Muscat, from 1 March 2014 to 30 April 2015, for the evaluation of an ovarian lesion. The inclusion criteria included women who underwent surgical intervention and who had a preoperative pelvic ultrasound with laboratory investigation for CA-125 and HE4. The study validated the diagnostic performance of CA-125, RMI, HE4, and ROMA using histopathological diagnosis as the gold standard. Results The study population had a total of 213 cases of various types of benign (77%) and malignant (23%) ovarian tumors. CA-125 showed the highest sensitivity (79%) when looking at the total patient population. When divided by age, the sensitivity was 67% in premenopausal women. In postmenopausal women, CA-125 had lower sensitivity (89%) compared to RMI, HE4, and ROMA (93% each). A high specificity of 90% was found for HE4 in the total patient population, 93% in premenopausal women and 75% in postmenopausal women. CA-125 had the highest specificity (79%) in postmenopausal women. Both CA-125 and RMI were frequently elevated in benign gynecological conditions particularly in endometriosis when compared to HE4 and ROMA. We also studied modifications of the optimal cut-offs for the four parameters. Both CA-125 and RMI showed a significant increase in their specificity if the cut-off was increased to ≥ 60 U/mL for CA-125 and to ≥ 250 for RMI. For HE4, we noted an improvement in its specificity in postmenopausal women when its cut-off was increased to140 pmol/L. Conclusions HE4 and ROMA showed a very high specificity, but were less sensitive than CA-125 and RMI in premenopausal women. However, they were of comparable sensitivity in postmenopausal women and were valuable in distinguishing benign ovarian tumors or endometriosis from ovarian cancer. Modifying the cut-off values of the different markers resulted in a higher accuracy compared to the standard cut-offs, but at the expense of reduced sensitivity.

Objective: We sought to determine the validity of cancer antigen 125 (CA-125) and the risk of malignancy index (RMI) in the diagnosis of ovarian cancer in women presenting with adnexal lesions of various histopathology types. Methods: This retrospective cross- sectional study included all women with adnexal lesions who were evaluated at the Royal Hospital, Oman, between January 2012 and December 2014. The inclusion criteria included women who underwent surgical intervention and who had preoperative CA-125 testing and pelvic ultrasound in the work-up plan of their management. The surgical intervention was usually followed by a histopathological diagnosis of the nature of the lesion, which was used as the gold standard for the evaluation of both CA-125 and RMI. Results: The cohort included 361 women who had serum CA-125 and pelvic ultrasound prior to the surgical intervention of the adnexal lesion. Of these women, 61 (17%) had malignant ovarian lesions. Using the proposed cut-off 35 U/ml for CA-125 and 200 for RMI, the CA-125 test was more sensitive for detecting the majority of malignant ovarian tumors compared to the RMI (69% vs. 57%). Both tests were more sensitive in detecting epithelial ovarian cancer compared to other ovarian cancers. However, RMI was more specific in excluding benign ovarian lesions compared to CA-125 (81% vs. 68%). Additionally, RMI had a better area under the curve compared to CA-125 (0.771 vs. 0.745; p

This is the first case report in Oman and the Gulf region of a 17-β-hydroxysteroid dehydrogenase type 3 (17-β-HSD3) deficiency with a novel mutation in the HSD17B3 gene that has not been previously described in the medical literature. An Omani child was diagnosed with 17-β-HSD3 deficiency and was followed up for 11 years at the Pediatric Endocrinology Clinic, Royal Hospital, Oman. He presented at the age of six weeks with ambiguous genitalia, stretched penile and bilateral undescended testes. Ultrasound showed no evidence of any uterine or ovarian structures with oval shaped solid structures in both inguinal regions that were confirmed by histology to be testicular tissues with immature seminiferous tubules only. The diagnosis was made by demonstrating low serum testosterone and high androstenedione, estrone, and androstenedione:testosterone ratio. Karyotyping confirmed 46,XY and the infant was raised as male. Testosterone injections (25mg once monthly) were given at two and six months and then three months before his surgeries at five and seven years of age when he underwent multiple operations for orchidopexy and hypospadias correction. At the age of 10 years he developed bilateral gynecomastia (stage 4). Laboratory investigations showed raised follicle-stimulating hormone, luteinizing hormone, androstenedione, and estrone with low-normal testosterone and low androstendiol glucurunide. Testosterone injections (50mg once monthly for six months) were given that resulted in significant reduction in his gynecomastia. Molecular analysis revealed a previously unreported homozygous variant in exon eight of the HSD17B3 gene (NM_000197.1:c.576G>A.Trp192*). This variant creates a premature stop codon, which is very likely to result in a truncated protein or loss of protein production. This is the first report in the medical literature of this novel HSD17B3 gene mutation. A literature review was conducted to identify the previous studies related to this disorder.

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 and 28 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.

OBJECTIVES The prevalence of coeliac disease in Oman is unknown. We aim to estimate the prevalence of coeliac disease in at-risk subjects, describe the clinical characteristics and laboratory findings associated with coeliac disease and the validity of serological testing for coeliac disease at the Royal Hospital, Oman over a period of three years. METHODS This is a retrospective case finding study. The medical and laboratory records were reviewed for patients for whom serum antiendomysium IgA antibodies were requested at the Royal Hospital during a 3-year period (1(st) Jan 2006-31(st) Dec 2008). The data were extracted in order to assess the following: a) Prevalence rate of coeliac disease among at-risk subjects; b) Clinical characteristics in patients with coeliac disease and clinical manifestations for which the requesting clinicians considered coeliac disease as a possible diagnosis, including their specialties; c) Laboratory tests results in patients with coeliac disease; and d) Validity of antiendomysium antibodies testing in comparison with histopathology of jejunal biopsies for diagnosing coeliac disease. RESULTS The study included 431 patients (250 females, 181 males) who were suspected of having (or screened for) coeliac disease. The median of age was 15 years (range: 9 months-74 years) with mean ± SD 18.95 ± 14.1 years. Of these, 15 (3.5%) patients (10 females, 5 males) with a median age of 19 years and mean 21.4 ± 13.0 years (range: 2.5-38 years), had positive antiendomysium antibodies results with median (range) of 160 (40-320) IU/L and mean± SD 204.5 ± 160 IU/L. Of these 15 patients, 13 had positive jejunal histopathological changes indicative of coeliac disease; the remaining 2 patients had no biopsy examination. Of the 44 patients with negative antiendomysium antibodies

Objectives: There are technical limitations for the currently available methods of measuring serum total and free testosteronein 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.Methods: This is a case control study that was conducted during the period from 1st May 2011 to 31st 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.Results: 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 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.Conclusion: 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.

A 50-year-old Omani woman presented to the Outpatient Clinic, Royal Hospital, Oman with right upper abdominal pain and backache that had lasted 10 days. She had no palpitation, sweating, or hypertension (blood pressure 122/78mmHg). The patient's history revealed that she had a similar incidence of abdominal pain two months prior, which was a "dull ache" in nature and somewhat associated with headache. The pain was relieved using a mild analgesic drug. Abdominal ultrasonography showed a right adrenal mass, and both computed tomography and magnetic resonance imaging of the adrenal glands confirmed a right adrenal mass consistent with adrenal pheochromocytoma. However, clinical biochemistry tests revealed normal levels of plasma catecholamines (dopamine, norepinephrine, and epinephrine) and metanephrine, which are unusual findings in adrenal pheochromocytoma. Meanwhile, the patient had markedly raised plasma normetanephrine (10-fold) which, together with the normal metanephrine, constitutes a metabolic profile that is compatible with extra-adrenal pheochromocytoma. The patient also had markedly raised chromogranin A (16-fold), consistent with the presence of a neuroendocrine tumor. Laparoscopic right adrenalectomy was done and the adrenal tumor was excised and retrieved in total. Histopathology and immunohistochemistry confirmed the diagnosis of adrenal pheochromocytoma; the tumor cells being positive for chromogranin, synaptophysin, and S-100 protein. Following surgery, the patient did well and showed full recovery at follow-up after three months. Molecular genetic testing showed no pathogenic mutation in pheochromocytoma genes: MAX, SDHA, SDHAF2, SDHB, SDHC, SDHD, VHL, and PRKAR1A. A review of the literature was conducted to identify the pathophysiology and any previous reports of such case. To our knowledge, this is the first report in Oman of the extremely rare entity of pheochromocytoma with an unusual clinical and biochemical scenario.

Objectives: To compare glucose values obtained using sodium flouride (NaF) tubes and serum separation tubes (SST) in a tertiary care hospital laboratory setting. Methods: This study was conducted at the Clinical Biochemistry Laboratory, Royal Hospital, Oman. During the study period (1 September–30 November 2013), 50 pairs (one NaF tube and one SST) of patient’s blood specimens were randomly collected. Following separation of plasma (NaF tubes) and serum (SST), glucose concentrations were measured by hexokinase assay using the Architect c8000. Fifteen pairs of these tubes were kept in the refrigerator at 4°C and plasma/serum glucose concentrations were measured daily up to seven days after collection. Results: Comparing plasma (NaF) and serum (SST) results of glucose values (n=50) showed an average difference of 0.00mmol/L (range -0.60 to +0.60mmol/L). Bland Altman analysis gave a non-significant constant bias of 0.10 ±0.195mmol/L (bias ±SD). Pearson correlation between plasma (NaF) and serum (SST) glucose concentrations revealed a significant correlation approaching unity with r2= 0.9991. No significant differences in glucose values were noted for both plasma and serum in 15 pairs of NaF and SST tubes when analyzed seven days following refrigeration. Hemolysis was observed in five (10%) NaF tubes compared with two (4%) SST. Conclusion: There is no difference in glucose values collected from plasma NaF tubes or serum SST, and so SST can be used in hospital laboratory settings as there are practical advantages, including cost-effectiveness and reduction in blood volume drawn when utilizing these tubes for glucose and other tests from a single blood collection tube.

Hemolysis is one of the most commonly encountered pre-analytical sources of interference in the Clinical Biochemistry laboratory. Hemolysis is known to cause a variable interference in both cardiac troponin I (cTnI) and troponin T (cTnT) assays. Each laboratory should determine and publicize these effects. In this experimental study we determined the effect of in-vitro sample hemolysis on both types of cardiac troponin assays and whether the effect was clinically significant

Objectives: This study aims to assess the usefulness of serum holotranscobalamin (holoTC), the fraction of vitamin B12 that is available for tissue uptake, compared with total vitamin B12 in patients investigated for vitamin B12 disorders. Methods: Serum samples were randomly selected from 76 patients (48 females, 28 males; age range 12-69 years) referred to the Clinical Biochemistry Laboratory, Royal Hospital for the assessment of vitamin B12 status. For each patient, serum total vitamin B12 level was determined by chemiluminescent microparticle immunoassay on Architect 2000 analyzer and holoTC (active vitamin B12) level was determined by microparticle enzyme immunoassay on Axsym analyzer (both from Abbott, USA). Results: Comparison of the data was conducted to reflect the mean, standard deviation (SD) and correlation coefficient between the two groups. The mean (SD) for serum holoTC and total vitamin B12 were 46.5(32.2) pmol/L and 316.3(165.6) pmol/L respectively. There was a significant correlation between holoTC and total vitamin B12 (r= 0.765, P< 0.001) and the regression equation was expressed as; y = a + bx (i.e: holoTC = 1.5 + 0.14 total vitamin B12). Also, the results were assessed for any misclassification when comparing holoTC and the total vitamin B12 in terms of whether each or both values agree or disagree for classifying the patients as having normal or abnormal (low or high) results, based on the cut-off thresholds of the kit’s quoted reference range for holo TC of 9-123 pmol/L and for total vitamin B12 of 140-600 pmol/L. Accordingly, in 69 (90.8%) samples, there was a parallel agreement/ classification of results, both being normal or abnormal. In 61 (80.4%) patients, both results were normal, whereas in 4 (5.2%) patients, both results were high, and in 4 (5.2%) patients both results were low. However, in 7 (9.8%) cases, there was disagreement/ misclassification of results; 6 (7.8%) patients, holoTC was normal while total vitamin B12 was low, and in 1 (1.4%) patient, holoTC was normal while total vitamin B12 was high. Conclusion: It can be recommended that holoTC and total vitamin B12, alone and in combination, have almost equal diagnostic efficiency in screening/diagnosing vitamin B12 deficiency for the majority of patients. In very few patients, holoTC appeared to be a better reflector of vitamin B12 status. Further comparison studies based on a gold standard method for classifying vitamin B12 status are worth considering.

25-hydroxyvitamin D, 25(OH)D is the most abundant vitamin D metabolite in the circulation, representing the best indicator of the nutritional status of this fat-soluble vitamin. Two distinct forms exist: 25(OH)D3 from cutaneously derived vitamin D (cholecalciferol), the predominant natural source of vitamin D in humans and 25(OH)D2 from vitamin D2 (ergocalciferol), derived almost entirely from supplementation or fortification of food.1 Worldwide, there has been an explosion of interest in the physiological, pathological, therapeutic and laboratory aspects of 25(OH)D. Request for its measurement has increased dramatically over the last few years with an annual increase of about 80-90%.2,3 At the Clinical Biochemistry Laboratory of the Royal Hospital, Muscat, Sultanate of Oman, the annual request rate for serum 25(OH)D during 2009 was at a much higher degree compared to 2007. The vast majority of patients tested were deficient in 25(OH)D. There is growing awareness for the role of vitamin D; not only for its role in metabolic bone disease, but also, the increasing recognition for its association with a variety of diseases. Several randomized controlled trials have revealed that vitamin D deficiency has been linked to the development of different chronic diseases such as cardiovascular diseases, autoimmune diseases, diabetes mellitus, neuromuscular dysfunction, chronic kidney diseases, different cancers, infections, and gynecological problems.4,5 Data from these studies mentioned earlier have demonstrated that circulating vitamin D is an important reflector of the total mortality risk.6 A recent prospective cohort study by Zittermann et al. in a specialized heart centre revealed that patients in the lowest quintiles of 1,25-dihydroxyvitamin D (1,25(OH)D, also termed calcitriol) and 25(OH)D were more likely to have coronary heart disease, heart failure, hypertension, diabetes mellitus or renal failure compared to patients with higher concentrations of 25(OH)D. The study also showed that low serum concentrations of 1,25(OH)D and 25(OH)D were related to higher 1-year mortality risk, while there was a significant decrease in 1-year mortality risk in patients with higher serum concentrations of vitamin D. The results were also consistent in patients representing different risk factors and multivariate risk adjustments such as age, body mass, smoking, aspirin use, renal function, inflammatory markers, and various co-morbidities.7 Other studies such as the study by Dobnig et al. which focused on the levels of vitamin D and cardiovascular mortality and a study by Wolf et al. which studied the levels of vitamin D and mortality in patients on hemodialysis also showed similar findings and have also confirmed such an association.6,8 Furthermore, meta analysis of different randomized controlled trials have revealed that vitamin D supplementation has been linked to lower total mortality in subjects with low 25(OH)D concentrations compared with un-supplemented individuals.9 Thus, it is worth providing 25(OH)D therapy or supplementation to high risk individuals without necessarily measuring their serum 25(OH)D concentrations, which may not be available at many laboratories. In addition to the increasing awareness regarding the key role of 25(OH)D in the maintenance of many physiological processes and recognition of its deficiency as a growing health problem, an analytical verification has to be addressed. Although there is no consensus on the optimal levels of serum 25(OH)D, most experts recommend that the standard level which confers its optimum physiological protective role and provides the full advantages of vitamin D health benefits is ≥75nmol/L (30 ng/ml).10 Vitamin D status has been defined at different 25(OH)D cut-offs, with levels: 50-74nmol/L (20-30 ng/ml) as suboptimal, 25-49 nmol/L (10-20 ng/ml) as insufficiency, 375nmol/L (150 ng/ml) or even at higher levels.5,10 With the use of such definitions, it has been estimated that one billion people worldwide have vitamin D deficiency or insufficiency, 40-100% of US and European elderly men and women are deficient in vitamin D and more than 50% of postmenopausal women taking medication for osteoporosis had suboptimal 25(OH)D levels