Humidity Fluctuation Beyond the Manufacture’s Acceptable Range in a Clinical Mass Spectrometry Laboratory Yuzi Zheng (Presenter) Cleveland Clinic Presenter Bio: I completed my PhD at the Centre for High-Throughput Biology at University of British Columbia (UBC), Canada, specializing in qualitative and quantitative proteomics. After my PhD, I was a postdoctoral research fellow in the Department of Pathology and Laboratory Medicine at UBC working in the clinical chemistry laboratory at St. Paul’s Hospital with research focused on translating biomarker research findings into quantitative mass spectrometry protein assays. Currently, I am a clinical chemistry fellow at Cleveland Clinic involved in development and validation of mass spectrometry assays for patient care.

Authors: Yuzi (Emma) Zheng (1), Philip Hunek (1), Mitchell McCale (1), Sihe Wang (1, 2) and Adam J. McShane (1)
(1) Cleveland Clinic, Cleveland, OH (2) Akron Children's Hospital, OH

The relative humidity fluctuates greatly in our clinical mass spectrometry laboratory. The lower relative humidity levels are below the manufacturer’s acceptance range of 40% to 70%. To determine the effect of humidity on test results and potentially establish a wider acceptable relative humidity range, the performance of quality control (QC) versus relative humidity was monitored. The QC results were from a urine pain management panel analyzed on liquid chromatography tandem mass spectrometry (LC-MS/MS) platforms. The gathered results had corresponding relative humidity readings from 26.4% to 59.6%. The QC results at all relative humidity readings were found to be within the 95% confidence interval of in-acceptance criteria QC analysis. Thus, the humidity range may be extended beyond the manufacture’s acceptable range.

Problem

Relative humidity fluctuates in the clinical mass spectrometry laboratory and will periodically fall outside the manufacture’s acceptable range. The fluctuation is due in large to the climate at our geographic location and insufficient compensation from the air-handling system.

Method Information

• Urine pain management LC-MS/MS panel

• Nineteen analytes analyzed in one method

• Two identical LC-MS/MS platforms

• Relative humidity readings were taken at times corresponding with QC analysis over 17 days, relative humidity range from 26.4% to 59.6%

• QC results for 19 analytes within one LC-MS/MS run were obtained over extreme fluctuations in relative humidity

• Statistical analysis based on the 95% confidence interval was performed

Troubleshooting Steps

Relative humidity was assessed during QC analysis. QC results for 19 analytes, within one LC-MS/MS analysis, were obtained over extreme fluctuations in relative humidity. Statistical analysis was performed to evaluate the effect of relative humidity outside the manufacturer’s acceptable range.

Outcome

QC results were acceptable and within the 95% confidence interval at relative humidity levels below the acceptable range provided by the manufacturer. A similar approach could be applied to evaluate relative humidity levels higher than the acceptable range or to other non-mass spectrometer instruments.