PMID- 37756097
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20231003
IS  - 2306-7381 (Electronic)
IS  - 2306-7381 (Linking)
VI  - 10
IP  - 9
DP  - 2023 Sep 15
TI  - Method Validation and Establishment of Reference Intervals for an Insulin-like 
      Growth Factor-1 Chemiluminescent Immunoassay in Cats.
LID - 10.3390/vetsci10090575 [doi]
LID - 575
AB  - Previously, radioimmunoassay (RIA) has been the only assay to measure 
      insulin-like growth factor-1 (IGF-1) to diagnose hypersomatotropism (HS). Due to 
      radiation concerns, availability, and the cost of IGF-1 RIA, validation of assays 
      for automated analysers such as a chemiluminescent immunoassay (CLIA) is needed. 
      The aim of this study was to validate a CLIA for measurement of feline IGF-1 
      (IMMULITE 2000((R)) XPi, Siemens Medical Solutions Diagnostics, Malvern, PA, USA) 
      compared to IGF1 RIA, establish reference interval (RI), and determine a cut-off 
      value for diagnosis of HS in diabetic cats. Validation of assay performance 
      included precision, linearity, and recovery studies. Right-sided RI was 
      determined using surplus serum of 50 healthy adult cats. Surplus serum samples of 
      diabetic cats with known IGF-1 concentration with (n = 32/68) and without HS (n = 
      36/68) were used for method comparison with RIA. The cut-off for diagnosis of HS 
      was established using receiver operating characteristic (ROC) analysis. The 
      intra-assay coefficient of variation (CV) was </=4.7%, and the inter-assay CV was 
      </=5.6% for samples with low, medium, and high IGF-1 concentration. Linearity was 
      excellent (R(2) > 0.99). The correlation between CLIA and RIA was very high (r(s) 
      = 0.97), with a mean negative bias for CLIA of 24.5%. The upper limit of RI was 
      670 ng/mL. ROC analysis showed an area under the curve of 0.94, with best cut-off 
      for diagnosis of HS at 746 ng/mL (sensitivity, 84.4%; specificity, 97.2%). The 
      performance of CLIA was good, and the RI and cut-off for HS diagnosis established 
      in this study allow for CLIA to be used in routine work-up of diabetic cats.
FAU - Gussow, Arne
AU  - Gussow A
AD  - Clinic for Small Animals (Internal Medicine, Clinical Pathology and Clinical 
      Pathophysiology), Justus-Liebig-University, 35392 Giessen, Germany.
FAU - Thalmeier, Sabine
AU  - Thalmeier S
AD  - Clinic for Small Animals (Internal Medicine, Clinical Pathology and Clinical 
      Pathophysiology), Justus-Liebig-University, 35392 Giessen, Germany.
FAU - Gostelow, Ruth
AU  - Gostelow R
AD  - Department of Clinical Science and Services, The Royal Veterinary College, 
      Hatfield AL9 7TA, UK.
FAU - Langenstein, Judith
AU  - Langenstein J
AD  - SYNLAB.vet GmbH, 86156 Augsburg, Germany.
FAU - Foerster, Gesine
AU  - Foerster G
AD  - SYNLAB.vet GmbH, 86156 Augsburg, Germany.
FAU - Bauer, Natali
AU  - Bauer N
AD  - Clinic for Small Animals (Internal Medicine, Clinical Pathology and Clinical 
      Pathophysiology), Justus-Liebig-University, 35392 Giessen, Germany.
FAU - Hazuchova, Katarina
AU  - Hazuchova K
AUID- ORCID: 0000-0002-7185-0446
AD  - Clinic for Small Animals (Internal Medicine, Clinical Pathology and Clinical 
      Pathophysiology), Justus-Liebig-University, 35392 Giessen, Germany.
LA  - eng
GR  - no grant number/Synlab (Germany)/
PT  - Journal Article
DEP - 20230915
PL  - Switzerland
TA  - Vet Sci
JT  - Veterinary sciences
JID - 101680127
PMC - PMC10534906
OTO - NOTNLM
OT  - IGF-1
OT  - cut-off
OT  - diabetes mellitus
OT  - feline
OT  - hypersomatotropism
OT  - precision
OT  - radioimmunoassay
OT  - reference range
COIS- J.L. and G.F. are employees of SYNLAB.vet GmbH. Sample measurement via IGF-1 CLIA 
      was performed and funded by SYNLAB.vet GmbH; however, the company was not 
      involved in the interpretation of the results. No other potential conflicts of 
      interest with respect to the research, authorship, and publication of this 
      article are declared.
EDAT- 2023/09/27 12:42
MHDA- 2023/09/27 12:43
PMCR- 2023/09/15
CRDT- 2023/09/27 11:54
PHST- 2023/08/10 00:00 [received]
PHST- 2023/09/10 00:00 [revised]
PHST- 2023/09/12 00:00 [accepted]
PHST- 2023/09/27 12:43 [medline]
PHST- 2023/09/27 12:42 [pubmed]
PHST- 2023/09/27 11:54 [entrez]
PHST- 2023/09/15 00:00 [pmc-release]
AID - vetsci10090575 [pii]
AID - vetsci-10-00575 [pii]
AID - 10.3390/vetsci10090575 [doi]
PST - epublish
SO  - Vet Sci. 2023 Sep 15;10(9):575. doi: 10.3390/vetsci10090575.