PMID- 30840691
OWN - NLM
STAT- MEDLINE
DCOM- 20191203
LR  - 20200309
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 14
IP  - 3
DP  - 2019
TI  - Expected total thyroxine (TT4) concentrations and outlier values in 531,765 cats 
      in the United States (2014-2015).
PG  - e0213259
LID - 10.1371/journal.pone.0213259 [doi]
LID - e0213259
AB  - BACKGROUND: Levels exceeding the standard reference interval (RI) for total 
      thyroxine (TT4) concentrations are diagnostic for hyperthyroidism, however some 
      hyperthyroid cats have TT4 values within the RI. Determining outlier TT4 
      concentrations should aid practitioners in identification of hyperthyroidism. The 
      objective of this study was to determine the expected distribution of TT4 
      concentration using a large population of cats (531,765) of unknown health status 
      to identify unexpected TT4 concentrations (outlier), and determine whether this 
      concentration changes with age. METHODOLOGY/PRINCIPLE FINDINGS: This study is a 
      population-based, retrospective study evaluating an electronic database of 
      laboratory results to identify unique TT4 measurement between January 2014 and 
      July 2015. An expected distribution of TT4 concentrations was determined using a 
      large population of cats (531,765) of unknown health status, and this in turn was 
      used to identify unexpected TT4 concentrations (outlier) and determine whether 
      this concentration changes with age. All cats between the age of 1 and 9 years (n 
      = 141,294) had the same expected distribution of TT4 concentration 
      (0.5-3.5ug/dL), and cats with a TT4 value >3.5ug/dL were determined to be 
      unexpected outliers. There was a steep and progressive rise in both the total 
      number and percentage of statistical outliers in the feline population as a 
      function of age. The greatest acceleration in the percentage of outliers occurred 
      between the age of 7 and 14 years, which was up to 4.6 times the rate seen 
      between the age of 3 and 7 years. CONCLUSIONS: TT4 concentrations >3.5ug/dL 
      represent outliers from the expected distribution of TT4 concentration. 
      Furthermore, age has a strong influence on the proportion of cats. These findings 
      suggest that patients with TT4 concentrations >3.5ug/dL should be more closely 
      evaluated for hyperthyroidism, particularly between the ages of 7 and 14 years. 
      This finding may aid clinicians in earlier identification of hyperthyroidism in 
      at-risk patients.
FAU - Lottati, Maya
AU  - Lottati M
AUID- ORCID: 0000-0001-5435-8006
AD  - VCA Veterinary Specialists of the Valley- Department of Internal Medicine, 
      Woodland Hills, CA, United States of America.
FAU - Aucoin, David
AU  - Aucoin D
AUID- ORCID: 0000-0001-7553-1242
AD  - VCA Antech, Los Angeles, CA, United States of America.
FAU - Bruyette, David S
AU  - Bruyette DS
AD  - Anivive Lifesciences, Long Beach, CA, United States of America.
LA  - eng
SI  - Dryad/10.5061/dryad.m6f721d
PT  - Journal Article
DEP - 20190306
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - 0 (Biomarkers)
RN  - Q51BO43MG4 (Thyroxine)
SB  - IM
MH  - Animals
MH  - Biomarkers/*blood
MH  - Cat Diseases/blood/*diagnosis/epidemiology
MH  - Cats
MH  - Female
MH  - Hyperthyroidism/blood/diagnosis/*veterinary
MH  - Male
MH  - Retrospective Studies
MH  - Thyroxine/*blood
MH  - Time Factors
MH  - United States/epidemiology
PMC - PMC6402689
COIS- Our affiliation with VCA Antech or Anivive Lifesciences does not alter our 
      adherence to PLOS ONE policies on sharing data and materials.
EDAT- 2019/03/07 06:00
MHDA- 2019/12/04 06:00
PMCR- 2019/03/06
CRDT- 2019/03/07 06:00
PHST- 2018/06/20 00:00 [received]
PHST- 2019/02/19 00:00 [accepted]
PHST- 2019/03/07 06:00 [entrez]
PHST- 2019/03/07 06:00 [pubmed]
PHST- 2019/12/04 06:00 [medline]
PHST- 2019/03/06 00:00 [pmc-release]
AID - PONE-D-18-18468 [pii]
AID - 10.1371/journal.pone.0213259 [doi]
PST - epublish
SO  - PLoS One. 2019 Mar 6;14(3):e0213259. doi: 10.1371/journal.pone.0213259. 
      eCollection 2019.