MTX	Methotrexate
MTX-PG	Methotrexate polyglutamate
IMID	Immune-mediated inflammatory diseases
Ped-ALL	Pediatric acute lymphoblastic leukemia
RA	Rheumatoid arthritis
JIA	Juvenile idiopathic arthritis
CD	Crohn’s diseases
FPGS	Folyl-polyglutamate synthetase
TDM	Therapeutic drug monitoring
SNP	Single nucleotide polymorphism
S.C.	Subcutaneous
I.V.	Intravenous
I.Th.	Intrathecal
DMARD	Disease-modifying anti-rheumatic drugs
HCQ	Hydroxychloroquine
SSZ	Sulfasalazine
UPLC-MS/MS	Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry
BMI	Body mass index
BSA	Body surface area
eGFR	Estimated glomerular filtration rate
CKD-EPI	Chronic Kidney Disease Epidemiology Collaboration
MICE	Multiple imputation by chained equations
SD	Standard deviation
IQR	Interquartile range
AO	Aldehyde oxidase
RFC	Reduced folate carrier
Km	Michaelis constant