A unilateral pelvic kidney with variant vasculature: clinical significance.

The incidence of ectopic pelvic kidney accounts for ~1 of 2500 live births. Although pelvic kidneys are most often asymptomatic, they may be associated with several pathologies including hypertension. As pelvic kidney results from a brief interference of the ascension of the developing kidney, it is frequently accompanied by an atypical and variable blood supply. The presence of multiple arteries and veins and their abnormal course and morphology are associated with surgical and radiological significance. Malrotation of the kidney with extrarenal calyces further predisposes the pelvic kidney to recurrent urinary tract infections. This report describes a rare case of a unilateral pelvic kidney with vascular and calyceal variations, and this case is reported to provide additional insight into this variation and its correlation to clinical practice.

Clinical Benefits of Direct-to-Definitive Testing for Monitoring Compliance in Pain Management.

BACKGROUND: The technical advantages of direct-to-definitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) urine testing for monitoring patient compliance in pain management are well known. However, the design and implementation of LC-MS/MS methods are more controversial, including factors such as determining appropriate cutoffs, specimen processing (e.g., specimen hydrolysis), reporting of qualitative and/or quantitative results, and test menu. OBJECTIVES: The objective of the research was to compare the clinical performance of our previous urine pain toxicology panel, a combination of immunoassay (IA) screens and LC-MS/MS, to our current pain toxicology panel, which features direct-to-definitive LC-MS/MS for 34 drugs and metabolites. STUDY DESIGN: Six months of results from our previous pain toxicology panel were compared to 5.5 months of results from our current pain toxicology panel, enabling us to make conclusions regarding clinical performance. SETTING: The research took place at Brigham and Women's Hospital in Boston, MA. METHODS: The percentage of false positive IA results was evaluated for our previous pain toxicology panel. The positivity rates for each drug and/or metabolite were calculated for both the previous and current panels, including rates of detection of both prescribed and illicit drugs. The turnaround time (TAT), direct and send-out costs associated with each approach, as well as projected cost savings were also determined. RESULTS: False positive rates with IA ranged from 0% to 29%; the highest false positive rate was seen for 6-acetylmorphine (6-AM). The elimination of IA, addition of metabolites, and/or lowering of cutoffs increased the detection rate of 6-AM, benzoylecgonine (cocaine metabolite), fentanyl, morphine, and oxycodone. The ability to differentiate compliance from simulated compliance improved after eliminating specimen hydrolysis. The TAT improved significantly and projected yearly cost savings with the current panel was $95,003 (USD). In our opinion, qualitative results appeared sufficient to assess compliance in the majority of cases. LIMITATIONS: Our study was performed in a single academic center in a specific geographic region; therefore, our results may not be generalizable to other types of centers or regions. CONCLUSION: Direct-to-definitive LC-MS/MS testing has several clinical benefits, including reduction of false positive results, improved assessment of patient compliance, decreased TAT, and increased detection of drug use and abuse. Cost savings were also realized using this approach. KEY WORDS: Direct-to-definitive, LC-MS/MS, immunoassay, sensitivity, cost, pain management, turnaround time, patient compliance.

Development and Validation of an Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry Method for the Concurrent Measurement of Gabapentin, Lamotrigine, Levetiracetam, Monohydroxy Derivative of Oxcarbazepine, and Zonisamide Concentrations in Serum in a Clinical Setting.

BACKGROUND: Therapeutic drug monitoring of antiepileptic drugs (AEDs) is often necessary to prevent associated destructive toxicities. Tandem mass spectrometry (MS/MS) with stable-isotope-labeled internal standards is considered the gold standard for the measurement of AEDs. This study presents the development and validation of a clinical ultra-performance liquid chromatography-MS/MS method for the concurrent measurement of gabapentin, lamotrigine, levetiracetam, monohydroxy derivative of oxcarbazepine, and zonisamide in human serum. METHODS: To determine the optimal assay analyte range, one year of AED therapeutic drug monitoring results (n = 1825) were evaluated. Simple protein precipitation with acetonitrile containing isotopically labeled internal standards was used. Reverse-phase ultra-performance liquid chromatography chromatographic separation was used, having a total run time of 3 minutes. Quantification of analytes was accomplished using electrospray ionization in positive ion mode and collision-induced dissociation MS. Assay parameters were evaluated per Food and Drug Administration bioanalytical guidelines. RESULTS: After evaluating internal patient data, the analytical measuring range (AMR) of the assay was established as 0.1-100 mcg/mL. All AEDs were linear across the AMR, with R values ranging from 0.9988 to 0.9999. Imprecision (% coefficient of variation) and inaccuracy (% difference) were calculated to be <20% for the lower limit of quantitation and <15% for the low, mid, and high levels of quality controls across the AMR. All AEDs demonstrated acceptable assay parameters for carryover, stability under relevant storage conditions, matrix effects, recovery, and extraction and processing efficiency. In addition, the assay displayed acceptable concordance to results obtained from a national reference laboratory, with Deming regression R of 0.99 and slope values ranging from 0.89 to 1.17. CONCLUSIONS: A simple, cost-effective, and robust ultra-performance liquid chromatography-tandem mass spectrometry method for monitoring multiple AEDs was developed and validated to address the clinical needs of patients at our institution.