Development of a CDC-certified total testosterone assay for adult and pediatric samples using LC-MS/MS.
Clin Mass Spectrom
; 13: 27-35, 2019 Aug.
Article
em En
| MEDLINE
| ID: mdl-34841083
ABSTRACT
BACKGROUND:
Highly accurate and sensitive method to measure testosterone in hypogonadal male, female and children is vital for proper diagnosis of hormone-related conditions and their treatment.OBJECTIVE:
To develop an accurate and robust total testosterone ESI-LC-MS/MS quantification method with a simple sample preparation workflow and sufficient sensitivity for serum or plasma samples of all gender and age groups, via ketone functional group derivatization (using Amplifex™ Keto Reagent).METHOD:
A simple sample preparation method to accommodate both low and high numbers of samples was developed using simultaneous protein precipitation and derivatization with Amplifex™ Keto reagent, followed by centrifugation and direct injection of supernatant into an LC-MS/MS system (SCIEX Topaz™ IVD LC-MS/MS, in which MS is equivalent to a SCIEX 4500MD Mass Spectrometer). Total testosterone in human serum or plasma samples was quantified using an external calibration curve generated by calibrators spanning a broad concentration range of â¼1-2000â¯ng/dL (10-20,000â¯pg/mL), traceable to NIST 971 SRM. 13C3-enriched testosterone was used as an internal standard to correct for both analyte loss during sample preparation and matrix effect during analysis (Supplementary Information SI Fig. 4C). Two methods, one using a 96-well filter plate and another using Eppendorf tubes, were developed. Both methods were certified by the Centers for Disease Control (CDC) hormone standardization (HoSt) program for total serum testosterone. The feasibility of implementing the method for plasma and serum samples was tested via a small-scale method comparison study between matched pediatric serum and plasma samples derived from the same donor. In addition, plasma samples originating from the same donor collected in two different anticoagulant tube types (Li-heparin and K2EDTA) were compared.RESULTS:
Using in-house formulated NIST 971-traceable calibrators, the method was linear (r2â¯>â¯0.999) between 1 and 2000â¯ng/dL (10 and 20,000â¯pg/mL) with a limit of detection of approximately 1â¯ng/dL (10â¯pg/mL). The testosterone concentration bias against 40 reference samples from the HoSt certification program was absolute <3% with an average %CV of â¼3-4%. More than 78% of samples passed the CDC bias criterion of ±6.4%. Comparison between pediatric matched serum and plasma samples resulted in high correlation (r2â¯=â¯0.997) and bias of <5%. The calculated % difference between matched adult serum and plasma samples was â¼1%.CONCLUSIONS:
Feasibility for an accurate and streamlined method suitable for measuring total testosterone in all human samples was demonstrated with a choice of sample preparation workflow to suit low or high number of samples. The method can potentially be used for plasma matrix from different blood collection tubes (Li-Heparin and K2EDTA).
Amplifex™ Keto Reagent; BSA, Bovine Serum Albumin; CDC certification; CDC, Center for Disease Control; CE, Collision Energy; CLSI, Clinical and Laboratory Standards Institute; CUR, Curtain Gas; CV, Coefficient of variation; CXP, Cell Exit Potential; Clinical assay; DP, Declustering Potential; Derivatization; ESI, Electrospray Ionization; ESI-LC-MS/MS; F, Female; Female and pediatric samples; HoSt certification program; HoSt, Hormone Standardization; IS, Internal Standard; IVD, In Vitro Diagnostic; K2EDTA; K2EDTA, Ethylenediaminetetraacetic acid dipotassium; LC-MS/MS, Liquid Chromatography-Mass Spectrometer (tandem); LLOQ, Lower Limit of Quantitation; Li, Lithium; Li-Heparin (LH); M, Male; MD, Medical Device; Matched patient sample; Max, Maximum; MeOH, Methanol; Min., Minimum; NIST, National Institute of Standards and Technology; Oxime; Plasma; Q, Quarter; S/N, Signal to Noise; Serum; Total testosterone; eV, electronvolt
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article