PB1330 - ADAMTS13 activity testing: a comparative study of semiquantitative flow-through assay and chemiluminescent method in a cohort of suspected thrombotic microangiopathy patients

Tuesday, June 25, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

NC

Nikolas R. Constantino

Biomedic
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
São Paulo, Sao Paulo, Brazil
RP

Rosana Penteado

Doctor
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
São Paulo, Sao Paulo, Brazil
AS

Andreza O. Santos

Biomedic
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
São Paulo, Sao Paulo, Brazil
DM

Denis Mello

pharmacist
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
São Paulo, Sao Paulo, Brazil
ES

Edson Silveira

pharmacist
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
São Paulo, Sao Paulo, Brazil
BF

Bruno Fogo

Biomedic
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.-
São Paulo, Sao Paulo, Brazil
AM

Ana Paula Moraes

Biologist
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
São Paulo, Sao Paulo, Brazil

Presenting Author(s)

JG

João Carlos Guerra

Doctor
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.-
São Paulo, Sao Paulo, Brazil

Background: ADAMTS13 is a plasma protease that cleaves ultra-large von Willebrand factor (VWF) multimers, preventing the formation of microvascular thrombi. Severe deficiency of ADAMTS13 activity is associated with thrombotic thrombocytopenic purpura (TTP), a life-threatening disorder that requires prompt diagnosis and treatment. Several methods have been developed to measure ADAMTS13 activity, including fluorescence resonance energy transfer (FRET) assays, enzyme-linked immunosorbent assays (ELISA), and automated platforms based on chemiluminescent technology.

Aims: The aim of this study was to compare the performance of two laboratory methodologies for ADAMTS13 activity testing in a cohort of patients with suspected Thrombotic Microangiopathy (TMA).

Methods: We randomly selected 20 citrated plasma samples from patients with suspected TMA and tested them for ADAMTS13 activity using two laboratory methods: a quantitative chemiluminescence-based assay (HEMOSIL® ACUSTAR ADAMTS13 ACTIVITY ASSAY, Werfen) and a semiquantitative flow-through assay (TECHNOSCREEN® ADAMTS13 Activity, Technoclone). The results of latter assay were read by four laboratory experts who recorded the estimated ADAMTS13 activity level obtained by the reference color chart.

Results: Four out of 20 samples were untestable by the Technoclone method due to plasma viscosity issues. The remaining 16 samples were evaluated by the observers who recorded the ADAMTS13 activity. The interobserver agreement showed significant consistency among the observers. However, when the Technoclone results were compared with the Werfen, the correlation between these two methods showed to be inconclusive and with no agreement beyond chance. Also, the correlation was low and not statistically significant for each observer, as indicated by high P-values.

Conclusion(s): Our study showed an inconclusive behavior between the Technoclone and Werfen methods, suggesting that they are not interchangeable in clinical practice. The Technoclone method also presented some technical difficulties that compromised its reliability. Further studies are needed to evaluate the performance of different methods for ADAMTS13 activity testing in various clinical scenarios.