Objective: To evaluate the quality of tandem mass spectrometry (MSMS) screening for neonatal inherited metabolic diseases in Zhejiang Province from 2009 to 2021. Methods: The data pertaining to MSMS screening for neonatal inherited metabolic diseases in Zhejiang Province from 2009 to 2021 were collected from the database created by Zhejiang Provincial Center for Neonatal Disease Screening. The percentage of MSMS screening, percentage of recall of suspected screening-positive infants and incidence of neonatal inherited metabolic diseases were analyzed retrospectively to evaluate the quality of MSMS screening for inherited metabolic diseases. Results: A total of 4 706 916 newborns were screened among 8 297 039 live births by MSMS in Zhejiang Province from 2009 to 2021, and the percentage of MSMS screening increased from 5.48% to 97.54%, with a mean percentage of 56.73%. Of 46 838 suspected screening-positive infants, 45 527 infants were recalled, and the percentage of recall increased from 94.57% to 98.62%, with a mean percentage of 97.20%. A total of 1 038 infants were definitively diagnosed with inherited metabolic diseases in Zhejiang Province from 2009 to 2021, with an overall incidence rate of 1/4 535, and the incidence rates of amino acid metabolic disorder, fatty acid oxidation metabolic disorder and organic acid metabolic disorder were 1/11 767, 1/13 763 and 1\15 902, respectively. Of the 11 cities in Zhejiang Province, the highest percentage of tandem mass spectrometry screening for inherited metabolic diseases was found in Hangzhou City (83.01%), and the highest percentage of recall of suspected screening-positive infants was se en in Zhoushan City (99.08%). Conclusions A high percentage of MSMS screening for neonatal inherited metabolic diseases was observed in Zhejiang Province from 2009 to 2021; however, there was a region-specific percentage of screening, and the recall of suspected screening-positive infants remains to be improved.

Abstract Transport of filter paper-dried blood spot samples is a critical procedure during the screening of neonatal inherited metabolic diseases, which is of great significance for the screening accuracy. In order to ensure the timing and safety of sample transport, the cold chain positioning system was initiated by Zhejiang Provincial Center for Quality Control of Neonatal Disease Screening since March 2015. Based on the framework of neonatal disease screening information management system, the function of the logistics transport management system was included in this positioning system, with aims to achieve the monitoring and tracking of sample transport processes through real-time positioning of the sample transport box via China Unicom 4G logistics card and global positioning system/BeiDou Navigation Satellite System. The samples are maintained in a transport environment at 2 to 8 °C via the temperature-controlled box made of 5 °C phase-changed cold-stored materials and general packet radio service (GPRS) temperature recorders. The mean pretest turnover duration reduced from 8.44 days to 5.03 days following introduction of the cold chain positioning system, and the percentage of timely sample delivery increased from 31.69% to 77.90%, while the withdrawal rate of unqualified samples reduced from 0.12% to 0.08%. The cold chain positioning system meets the requirements of transport of filter paper-dried blood spot samples, which has a high potential in screening of neonatal inherited metabolic diseases.