High-sensitive detection and quantitation of thyroid-stimulating hormone (TSH) from capillary/fingerstick and venepuncture whole-blood using fluorescence-based rapid lateral flow Immunoassay (LFIA)

Abstract

AbstractBackgroundIn the last decade, point of care testing (POCT) such as lateral flow immunoassays (LFIA) were developed for rapid TSH measurement. Most of these TSH-LFIAs are designed for qualitative measurements (i.e., if TSH values >5, or >15 IU/L) and as screening tests for primary hypothyroidism in children and adults. Serum or plasma, but not venepuncture whole-blood, or fingerstick/capillary, are usually used for accurate quantitation of TSH. Studies on performance evaluation of TSH-LFIAs POCT using venepuncture or fingerstick whole-blood are limited.AimWe aim to evaluate the performance of a new fluorescence-based LFIA and its Finecare™ fluorescent reader for quantitative measurement of TSH from a fingerstick, venepuncture whole-blood, and serum.Methods102 fingerstick, venepuncture whole-blood, and serum samples (with normal and abnormal TSH values) were analyzed by Finecare™ Rapid Quantitative LFIA test and Roche CobasPro-c503 as a reference test.ResultsUsing serum, when compared to CobasPro-c503 reference method, Finecare™ showed high sensitivity (90.5%) and specificity (96.3%) for diagnosis of thyroid abnormalities (<0.35 or > 4.5 mIU/L). The actual test values (mIU/L) of Finecare™ showed excellent agreement (Cohen’s Kappa=0.85) and strong correlation (r=0.93, p<0.0001) with CobasPro-c503. Using venepuncture whole-blood samples, Finecare™ showed similar results to serum with high sensitivity (95.2%), specificity (97.5%), excellent agreement (Cohen’s Kappa=0.91), and very strong correlation (r=0.95, p<0.0001) with CobasPro-c503. These results suggest that Finecare™ can be used for quantitative measurement of TSH using serum or venepuncture whole-blood. These key performance indicators were slightly decreased when fingerstick whole-blood samples were used: Sensitivity (85.7%), specificity (90.0%), good agreement (Cohen’s Kappa=0.7) and very strong correlation (r=0.9, p<0.0001) with CobasPro-c503.ConclusionOur results indicate that the Finecare™ is appropriate for TSH screening and quantitative measurement of TSH using serum samples and fingersticks, particularly in none or small laboratory settings.HighlightsFinecare presented high sensitivity & specificity for diagnosing thyroid diseasesStrong correlations were observed between Finecare and the reference methodSample types (serum, venepuncture, fingerstick) do not affect TSH Finecare resultsFingerstick/capillary sample is appropriate for TSH quantitation by Finecare