The utility of ESR, CRP and platelets in the diagnosis of GCA

Fiona Li Ying Chan,Samuel Lawrence Whittle,Catherine Louise Hill,Susan Lester

doi:10.1186/s41927-019-0061-z

Fiona Li Ying Chan, Samuel Lawrence Whittle + Show 2 more

Open Access

https://doi.org/10.1186/s41927-019-0061-z

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Journal: BMC rheumatology	Publication Date: Apr 10, 2019
Citations: 36	License type: open-access

Affiliation: Queen Elizabeth Hospital

Abstract

BackgroundTo compare the utility of ESR, CRP and platelets for the diagnosis of GCA.MethodA clinical diagnosis of GCA was determined by case-note review of 270 individuals (68% female, mean age 72 years) referred to a central pathology service for a temporal artery biopsy between 2011 and 2014. The highest levels of ESR, CRP and platelets (within 2 weeks of diagnosis) were documented. Evaluation of ESR, CRP and platelets for the diagnosis of GCA were compared using Receiver Operating Characteristic Area Under the Curve (ROC-AUC), and sensitivity/specificity at optimum cut-off values.ResultsGCA was clinically diagnosed in 139 (67%) patients, with 81 TAB positive. The AUC estimates for ESR, CRP and platelets were comparable (0.65 vs 0.72 vs 0.72, p = 0.08). The estimated optimal cut-off levels were confirmed at 50 mm/hour for ESR, and determined as 20 mg/L for CRP and 300 × 109/L for platelets. Sensitivity estimates for these three tests were comparable (p = 0.45) and ranged between 66% for ESR and 71% for platelets. Specificity estimates were also comparable (p = 0.11) and ranged between 57% for ESR and 68% for CRP. There was only moderate agreement between the three positive tests (agreement 67%, kappa: 0.34), and when considered collectively, CRP and platelet positive tests were independent predictors of GCA (p < 0.001), but the ESR was not (p = 0.76).ConclusionESR, CRP and platelets are moderate, equivalent diagnostic tests for GCA, but may yield disparate results in individual patients. A combination of CRP and platelet tests may provide the best diagnostic utility for GCA.

Highlights

To compare the utility of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and platelets for the diagnosis of Giant cell arteritis (GCA)
The purpose of this study was to review the utility of ESR, CRP and platelet count in the initial diagnostic process for GCA to aid in clinical situations where there is a discordance between the laboratory results
The highest recorded values for ESR, CRP and platelet count within a two-week period prior to biopsy were recorded from Oacis (South Australian state-wide electronic medical record system) and from physician documentation in paper medical records

Summary

Introduction

To compare the utility of ESR, CRP and platelets for the diagnosis of GCA. Giant cell arteritis (GCA) is a vasculitis of large and medium-sized vessels and is considered he most common form of vasculitis in the white population over the age of 50 [1] with official descriptions present since 1932 [2]. The sensitivity rates vary according to the cranial or large-vessel phenotypes of GCA. Rapid diagnosis and management is paramount in GCA due to its potential to cause irreversible vision loss [5]. The purpose of this study was to review the utility of ESR, CRP and platelet count in the initial diagnostic process for GCA to aid in clinical situations where there is a discordance between the laboratory results. The American College of Rheumatology research classification criteria for GCA requires three or more of the following five criteria [6]: Age 50 years and older, new onset of localized headache, temporal artery tenderness on palpation or decreased pulsation, an abnormal temporal artery

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