Utility of blood tests in screening for metabolic disorders in kidney stone disease.

OBJECTIVES: To determine the clinical utility of blood tests as a screening tool for metabolic abnormalities in patients with kidney stone disease. SUBJECTS AND METHODS: Clinical and biochemical data from 709 patients attending the Oxford University Hospitals NHS Foundation Trust for assessment and treatment of kidney stones were prospectively collected between April 2011 and February 2017. Data were analysed to determine the utility of serum calcium, parathyroid hormone (PTH), urate, chloride, bicarbonate, potassium and phosphate assays in screening for primary hyperparathyroidism, normocalcaemic hyperparathyroidism, hyperuricosuria, distal renal tubular acidosis (dRTA) and hypercalciuria. RESULTS: An elevated serum calcium level was detected in 2.3% of patients. Further investigations prompted by this finding resulted in a diagnosis of primary hyperparathyroidism in 0.2% of men and 4.6% of women for whom serum calcium was recorded. An elevated serum PTH level in the absence of hypercalcaemia was detected in 15.1% of patients. Of these patients, 74.6% were vitamin D-insufficient; no patients were diagnosed with normocalcaemic hyperparathyroidism. Hyperuricosuria was present in 21.6% of patients and hypercalciuria in 47.1%. Hyperuricaemia was not associated with hyperuricosuria, nor was hypophosphataemia associated with hypercalciuria. No patient was highlighted as being at risk of dRTA using serum chloride and bicarbonate as screening tests. CONCLUSION: This study indicates that individuals presenting with renal calculi should undergo metabolic screening with a serum calcium measurement alone. Use of additional blood tests to screen for metabolic disorders is not cost-effective and may provide false reassurance that metabolic abnormalities are not present. A full metabolic assessment with 24-h urine collection should be undertaken in recurrent stone formers and in those at high risk of future stone disease to identify potentially treatable metabolic abnormalities.

Comparison of Prostate Biopsy with or without Prebiopsy Multiparametric Magnetic Resonance Imaging for Prostate Cancer Detection: An Observational Cohort Study.

PURPOSE: We hypothesized that 1) introducing prebiopsy multiparametric magnetic resonance imaging would increase the diagnostic yield of transrectal prostate biopsy and 2) this would inform recommendations regarding systematic transrectal prostate biopsy in the setting of negative prebiopsy multiparametric magnetic resonance imaging. MATERIALS AND METHODS: A total of 997 biopsy naïve patients underwent transrectal prostate biopsy alone to June 2016 (cohort 1) and thereafter 792 underwent transrectal prostate biopsy following prebiopsy multiparametric magnetic resonance imaging (cohort 2). Patients with lesions on prebiopsy multiparametric magnetic resonance imaging underwent cognitive targeted plus systematic transrectal prostate biopsy. Patients without lesions underwent systematic transrectal prostate biopsy. RESULTS: Cohort 2 comprised younger men (age 68 vs 69 years, p = 0.01) with lower prostate specific antigen (7.6 vs 7.9 ng/ml, p = 0.024) and smaller prostate volume (56.1 vs 62 cc, p = 0.006). In cohort 2 vs cohort 1 there was no increase in overall prostate cancer detection (57.6% vs 56.7%, p = 0.701), the Gleason Grade Group or the number of positive cores (each p >0.05). Increased multifocal prostatic intraepithelial neoplasia, maximum prostate cancer core length (5 mm or greater vs less than 5 mm) and radical surgery/high intensity focused ultrasound (each p <0.05) were observed in cohort 2. For Gleason Grade Group 2-5 prostate cancer negative prebiopsy multiparametric magnetic resonance imaging had 88.1% sensitivity, 59.8% specificity, 67.8% positive predictive value and 84% negative predictive value. For negative prebiopsy multiparametric magnetic resonance images a prostate specific antigen density cutoff of 0.15 ng/ml2 or greater increased clinically significant prostate cancer detection only if the latter was defined as Gleason Grade Group 3-5 disease and/or tumor length 6 mm or greater. CONCLUSIONS: Introducing prebiopsy multiparametric magnetic resonance imaging in our clinical setting increased the diagnostic yield of prostate cancer per biopsy core. Not performing a systematic transrectal prostate biopsy when prebiopsy multiparametric magnetic resonance imaging was negative would have led to under detection of 15.1% of Gleason Grade Group 2 or greater prostate cancer cases (approximately 1 in 6).