1.Calibration Practices in Clinical Mass Spectrometry: Review and Recommendations
Wan Ling CHENG ; Corey MARKUS ; Chun Yee LIM ; Rui Zhen TAN ; Sunil Kumar SETHI ; Tze Ping LOH ;
Annals of Laboratory Medicine 2023;43(1):5-18
Background:
Calibration is a critical component for the reliability, accuracy, and precision of mass spectrometry measurements. Optimal practice in the construction, evaluation, and implementation of a new calibration curve is often underappreciated. This systematic review examined how calibration practices are applied to liquid chromatography-tandem mass spectrometry measurement procedures.
Methods:
The electronic database PubMed was searched from the date of database inception to April 1, 2022. The search terms used were “calibration,” “mass spectrometry,” and “regression.” Twenty-one articles were identified and included in this review, following evaluation of the titles, abstracts, full text, and reference lists of the search results.
Results:
The use of matrix-matched calibrators and stable isotope-labeled internal standards helps to mitigate the impact of matrix effects. A higher number of calibration standards or replicate measurements improves the mapping of the detector response and hence the accuracy and precision of the regression model. Constructing a calibration curve with each analytical batch recharacterizes the instrument detector but does not reduce the actual variability. The analytical response and measurand concentrations should be considered when constructing a calibration curve, along with subsequent use of quality controls to confirm assay performance. It is important to assess the linearity of the calibration curve by using actual experimental data and appropriate statistics. The heteroscedasticity of the calibration data should be investigated, and appropriate weighting should be applied during regression modeling.
Conclusions
This review provides an outline and guidance for optimal calibration practices in clinical mass spectrometry laboratories.
2.Performance of the CKD-EPI creatinine-cystatin C glomerular filtration rate estimation equations in a multiethnic Asian population.
Boon Wee TEO ; Yun Yin KOH ; Qi Chun TOH ; Jialiang LI ; Arvind Kumar SINHA ; Borys SHUTER ; Sunil SETHI ; Evan J C LEE
Singapore medical journal 2014;55(12):656-659
INTRODUCTIONClinical practice guidelines recommend using creatinine-based equations to estimate glomerular filtration rates (GFRs). While these equations were formulated for Caucasian-American populations and have adjustment coefficients for African-American populations, they are not validated for other ethnicities. The Chronic Kidney Disease-Epidemiology Collaborative Group (CKD-EPI) recently developed a new equation that uses both creatinine and cystatin C. We aimed to assess the accuracy of this equation in estimating the GFRs of participants (healthy and with chronic kidney disease [CKD]) from a multiethnic Asian population.
METHODSSerum samples from the Asian Kidney Disease Study and the Singapore Kidney Function Study were used. GFR was measured using plasma clearance of 99mTc-DTPA. GFR was estimated using the CKD-EPI equations. The performance of GFR estimation equations were examined using median and interquartile range values, and the percentage difference from the measured GFR.
RESULTSThe study comprised 335 participants (69.3% with CKD; 38.5% Chinese, 29.6% Malays, 23.6% Indians, 8.3% others), with a mean age of 53.5 ± 15.1 years. Mean standardised serum creatinine was 127 ± 86 μmol/L, while mean standardised serum cystatin C and mean measured GFR were 1.43 ± 0.74 mg/L and 67 ± 33 mL/min/1.73 m2, respectively. The creatinine-cystatin C CKD-EPI equation performed the best, with an estimated GFR of 67 ± 35 mL/min/1.73 m2.
CONCLUSIONThe new creatinine-cystatin C equation estimated GFR with little bias, and had increased precision and accuracy in our multiethnic Asian population. This two-biomarker equation may increase the accuracy of population studies on CKD, without the need to consider ethnicity.
Adult ; Aged ; Biomarkers ; blood ; urine ; China ; ethnology ; Creatinine ; blood ; Cystatin C ; blood ; Female ; Glomerular Filtration Rate ; Healthy Volunteers ; Humans ; India ; ethnology ; Malaysia ; ethnology ; Male ; Middle Aged ; Models, Statistical ; Prospective Studies ; Renal Insufficiency, Chronic ; blood ; urine ; Reproducibility of Results
3.Clinical efficacy and long-term immunogenicity of an early triple dose regimen of SARS-CoV-2 mRNA vaccination in cancer patients.
Matilda Xinwei LEE ; Siyu PENG ; Ainsley Ryan Yan Bin LEE ; Shi Yin WONG ; Ryan Yong Kiat TAY ; Jiaqi LI ; Areeba TARIQ ; Claire Xin Yi GOH ; Ying Kiat TAN ; Benjamin Kye Jyn TAN ; Chong Boon TEO ; Esther CHAN ; Melissa OOI ; Wee Joo CHNG ; Cheng Ean CHEE ; Carol L F HO ; Robert John WALSH ; Maggie WONG ; Yan SU ; Lezhava ALEXANDER ; Sunil Kumar SETHI ; Shaun Shi Yan TAN ; Yiong Huak CHAN ; Kelvin Bryan TAN ; Soo Chin LEE ; Louis Yi Ann CHAI ; Raghav SUNDAR
Annals of the Academy of Medicine, Singapore 2023;52(1):8-16
INTRODUCTION:
Three doses of SARS-CoV-2 mRNA vaccines have been recommended for cancer patients to reduce the risk of severe disease. Anti-neoplastic treatment, such as chemotherapy, may affect long-term vaccine immunogenicity.
METHOD:
Patients with solid or haematological cancer were recruited from 2 hospitals between July 2021 and March 2022. Humoral response was evaluated using GenScript cPASS surrogate virus neutralisation assays. Clinical outcomes were obtained from medical records and national mandatory-reporting databases.
RESULTS:
A total of 273 patients were recruited, with 40 having haematological malignancies and the rest solid tumours. Among the participants, 204 (74.7%) were receiving active cancer therapy, including 98 (35.9%) undergoing systemic chemotherapy and the rest targeted therapy or immunotherapy. All patients were seronegative at baseline. Seroconversion rates after receiving 1, 2 and 3 doses of SARS-CoV-2 mRNA vaccination were 35.2%, 79.4% and 92.4%, respectively. After 3 doses, patients on active treatment for haematological malignancies had lower antibodies (57.3%±46.2) when compared to patients on immunotherapy (94.1%±9.56, P<0.05) and chemotherapy (92.8%±18.1, P<0.05). SARS-CoV-2 infection was reported in 77 (28.2%) patients, of which 18 were severe. No patient receiving a third dose within 90 days of the second dose experienced severe infection.
CONCLUSION
This study demonstrates the benefit of early administration of the third dose among cancer patients.
Humans
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SARS-CoV-2
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COVID-19/prevention & control*
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Treatment Outcome
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Neoplasms/drug therapy*
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Hematologic Neoplasms
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Vaccination
;
RNA, Messenger
;
Antibodies, Viral
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Immunogenicity, Vaccine