Background: In November 2018, a consensus article was published across six major journals, collectively referred to as the 2018 Consensus. This document not only introduced the nomenclature for perioperative neurocognitive disorders (PNDs) but also proposed a redefinition of the diagnostic criteria for postoperative cognitive dysfunction (POCD) in accordance with the Diagnostic and Statistical Manual of Mental Disorders-5th edition (DSM-V). These criteria notably diverge from the ISPOCD1 standards that were prevalent in prior clinical studies. Objective: To explore the current status of assessment and diagnostic methods used in POCD clinical research following the release of the 2018 Consensus. Methods: A comprehensive literature search was executed utilizing the PubMed platform, focusing on clinical research articles related to postoperative cognitive dysfunction published between January 1, 2019, and June 1, 2024. The relevant literature was meticulously screened, and a synthesis was undertaken to summarize the neuropsychological assessment instruments, diagnostic approaches for POCD, and the timing of assessments across the studies. Results: A total of 89 studies from 25 countries or regions were included. The objective neuropsychological assessment tools used were categorized into four neurocognitive domains: learning and memory, attention and executive function, language, and visual perception. Regarding the diagnosis of POCD, only three studies utilized the 2018 Consensus criteria, ten studies adopted the ISPOCD1 criteria, and all studies analyzed the neuropsychological assessment results based on the reliable change index (RCI). The most common POCD assessment times were on the 7th postoperative day or at discharge and three months postoperatively. Conclusion: Over five years subsequent to the promulgation of the 2018 Consensus, there are still few clinical studies using DSM-V diagnostic criteria. The majority of studies persist in employing the ISPOCD1 criteria or analogous benchmarks. Furthermore, a considerable variability exists in the timing of POCD assessments among studies, accompanied by a diverse array of cognitive assessment instruments being utilized.