A review of molecular testing for thyroid nodules: accuracy and limitations

December 2022 Science Nalinee Pandey

A systematic review and meta-analysis of studies about molecular tests used to assess malignancy in thyroid nodules revealed that these tests are highly sensitive despite several limitations. These findings were published in the journal Thyroid.

Although molecular tests for thyroid nodules are increasingly used in the clinic, their true accuracy remains unknown. Towards this end, the researchers conducted a systematic review and meta-analysis of studies about these tests. There are four commonly used tests for assessing thyroid nodules. This includes Afirma gene expression classifiers, Afirma genomic sequencing classifier, ThyroSeq versions 1 and 2, and ThyroSeq version 3.

The researchers searched publication databases such as Pubmed, Embase and Web of science up until July 2021 and included 49 studies in the systematic review and meta-analysis. Among these, thirty-five studies analysed afirma gene expression classifiers, nine analysed Afirma genomic sequencing classifier, and one analysed both the Afirma tests. Additionally, 39 studies were retrospective, nine prospective, and one retrospective and prospective cohort.

The meta-analysis found that the Afirma gene expression classifier studies had a sensitivity of 92% and a specificity of 26%. Further, the Afirma genomic sequencing classifier had a sensitivity and specificity of 94% and 38%, ThyroSeq version 1 and 2 had 86% and 74%, and ThyroSeq version 3 had 92% and 41%, respectively. In addition, the researchers found several limitations associated with these studies, such as a lack of correction for partial verification bias accounting for possible false-negative results, a lack of masked histopathologic review in most studies, and inconsistencies on whether to classify noninvasive follicular thyroid neoplasm with papillary-like nuclear features as benign or malignant.

The researchers concluded, “Our results, in addition to prior systematic reviews of molecular tests for thyroid cancer, bolster the conclusions of the majority of studies reviewed, including the industry-sponsored studies, which are that molecular tests for indeterminate thyroid nodules have the potential to aid in clinical decision-making; however, solidifying this finding warrants further investigations.”


DiGennaro C, Vahdatzad V, Jalali MS, et al. Assessing Bias and Limitations of Clinical Validation Studies of Molecular Diagnostic Tests for Indeterminate Thyroid Nodules: Systematic Review and Meta-Analysis. Thyroid. 2022 Oct;32(10):1144-1157. doi: 10.1089/thy.2022.0269.