Squaring the circle – Making routine TSH assays to agree

Apr
10
2018

Analytica Conference > DGKL / Room 4a > Novel aspects of hormone analysis

10. Apr 2018
10:00-10:40 h  |  ICM - Internationales Congress Center München Room 4a

Additional informations in detail view:
o Attachments
o Presscontact
o Alternative Events

Details

Subjects: 

Pharma & Diagnostics

|

Medicine/public health

|

Biotechnology & Life Sciences

|

Analytic

Speaker: 

Prof. Dr. Linda Thienpont 

(Thienpont & Stöckl Wissenschaftliches Consulting GbR)

Type:
Lecture
Speech: English

In the discipline of laboratory medicine there is consensus about the measurement paradigm that states that routine assays claiming the same measurand should give equivalent results (= equal- within agreed upon performance specifications). This is paramount for application of consistent standards of medical care and disease prevention. Equivalency is ideally achieved by applying a metrological traceability chain or reference measurement system (RMS) for calibration of routine assays. Key elements in the RMS are the definition of the measurand (component-system-kind of quantity; SI-units), the reference material to realize the SI and the reference method/ procedure to assign values to the routine assays’ working calibrators. However, for TSH immunoassays (IAs), it is unlikely to accomplish such a RMS in mid-term. A major hurdle is the difficulty to unequivocally define the component in the measurand, as TSH in serum is a mixture (different isoforms and glycosylation). For the same reason IA results are not expressed in SI but arbitrary units defined by the WHO TSH standard (80/558 and 81/565; derived from the same pituitary extract).

There is sufficient evidence that TSH IAs violate the measurement paradigm in spite of their calibration being traceable to the WHO standard. This is due to the latter’s non-commutability, i.e., it does not give an identical dose/response relationship in IAs as the TSH mixture in serum. To solve this problem, the IFCC Committee for Standardization of Thyroid Function Tests (C-STFT) proposed to harmonize IAs with a new measurement standard: a panel of clinical samples to be used in a multiassay method comparison (MC) and assigned with target values for IA recalibration. For the target setting from the MC results, a statistical factor analysis model was developed. As I will explain, this pragmatic approach meets the metrological requirement of defining the measurand commensurate with its realization in the proposed measurement standard, “TSH, intact, total, glycosylation encountered in diagnostic applications which should be specified”. However, I will also emphasize that the approach requires fulfillment of certain medical, analytical and physiological circumstances.

C-STFT showed in a recent Phase IV MC study that the approach worked for harmonization of 14 IAs, so that most meet biological bias and total error specifications. A subsequent reference interval (RI) study gave the proof-of-concept that the recalibrated IAs can adopt a more uniform RI. However, this is not the endpoint: before implementation, everything has to be done to mitigate interpretation errors due to the impact of recalibration on future results and RIs. For relevant references, see [1].

[1] Thienpont LM. et al., on behalf of the IFCC C-STFT. Clin. Chem. 2017,63:1248-60.

Speaker
Prof. Dr. Linda Thienpont, Thienpont & Stöckl Wissenschaftliches Consulting GbR Show Profile

Location
Outdoor areas
EntranceNorth-East
EntranceNorth-West
EntranceNorth
ConferenceCenter Nord
ICM -InternationalesCongressCenterMünchen
B0
C1
C2
C3
C4
C5
C6
B1
B2
B3
B4
B5
B6
EntranceWest
Atrium
A1
A2
A3
A4
A5
A6
EntranceEast
EntranceNorth-West
EntranceNorth
Outdoor areas
EntranceNorth-East
ConferenceCenter Nord
ICM
B0
C1
C2
C3
C4
C5
C6
B1
B2
B3
B4
B5
B6
EntranceWest
Atrium
EntranceEast
A1
A2
A3
A4
A5
A6
Apr
10
2018

Analytica Conference > DGKL / Room 4a > Novel aspects of hormone analysis

Harmonization of LC-MS/MS assays for circulating steroid profiling

10. Apr 2018
11:20-11:40 h  |  ICM - Internationales Congress Center München Room 4a
Speaker: Dr. Flaminia Fanelli (Università di Bologna)

Additional informations in detail view:
o Attachments
o Presscontact
o Alternative Events

Details
Apr
10
2018

Analytica Conference > DGKL / Room 4a > Novel aspects of hormone analysis

Clinical endocrine mass spectrometry

10. Apr 2018
10:40-11:00 h  |  ICM - Internationales Congress Center München Room 4a
Speaker: Prof. Stefan Grebe (Mayo Clinic)

Additional informations in detail view:
o Attachments
o Presscontact
o Alternative Events

Details
Apr
10
2018

Analytica Conference > DGKL / Room 4a > Novel aspects of hormone analysis

Interference of biotin in endocrine assays

10. Apr 2018
11:40-12:00 h  |  ICM - Internationales Congress Center München Room 4a
Speaker: Dr. Martin Bidlingmaier (Klinikum der Universität München)

Additional informations in detail view:
o Attachments
o Presscontact
o Alternative Events

Details