To evaluate if procalcitonin (PCT) measurements made using the new point-of-care testing (POCT) ichroma™ are interchangeable with those made using Kryptor. Serum samples (n = 117) were processed sequentially on Kryptor and ichroma™. Statistical analysis was performed using Passing-Bablok (PB) regression and the Bland-Altman (BA) test. Cohen's kappa statistic was used to calculate the concordance at the clinically relevant cutoffs. PB regression did not show a significant deviation from linearity; proportional and constant differences were observed between ichroma™ and Kryptor. The 95% confidence interval (CI) of the mean bias percentage was very large, exceeding the maximum allowable total error (TE) (approximately 20%) and the clinical reference change value (about 60%). However, the concordance between methods at the clinically relevant cutoffs was strong, with the exception of the 0.25 ng/mL cutoff, which was moderate. Our data suggest that ichroma™ is not interchangeable with Kryptor, so cannot be mixed; one must choose one instrument only and be consistent. However, while the strong concordance at the clinically relevant cutoffs allows us to consider ichroma™ a suitable option to Kryptor to support clinicians' decision-making, nevertheless the moderate agreement at the 0.25 ng/mL cutoff recommends caution in interpreting the data around this cutoff.

Agreement between procalcitonin measurements using the new point-of-care testing ichroma™ reader and the automated Kryptor instrument

Stenner E.
;
Barbati G.;
2019

Abstract

To evaluate if procalcitonin (PCT) measurements made using the new point-of-care testing (POCT) ichroma™ are interchangeable with those made using Kryptor. Serum samples (n = 117) were processed sequentially on Kryptor and ichroma™. Statistical analysis was performed using Passing-Bablok (PB) regression and the Bland-Altman (BA) test. Cohen's kappa statistic was used to calculate the concordance at the clinically relevant cutoffs. PB regression did not show a significant deviation from linearity; proportional and constant differences were observed between ichroma™ and Kryptor. The 95% confidence interval (CI) of the mean bias percentage was very large, exceeding the maximum allowable total error (TE) (approximately 20%) and the clinical reference change value (about 60%). However, the concordance between methods at the clinically relevant cutoffs was strong, with the exception of the 0.25 ng/mL cutoff, which was moderate. Our data suggest that ichroma™ is not interchangeable with Kryptor, so cannot be mixed; one must choose one instrument only and be consistent. However, while the strong concordance at the clinically relevant cutoffs allows us to consider ichroma™ a suitable option to Kryptor to support clinicians' decision-making, nevertheless the moderate agreement at the 0.25 ng/mL cutoff recommends caution in interpreting the data around this cutoff.
Pubblicato
https://www.degruyter.com/view/j/labm.2019.43.issue-3/labmed-2018-0179/labmed-2018-0179.xml
File in questo prodotto:
File Dimensione Formato  
Stenner 2019.pdf

non disponibili

Tipologia: Documento in Versione Editoriale
Licenza: Digital Rights Management non definito
Dimensione 179.58 kB
Formato Adobe PDF
179.58 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2957791
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact