Digital revolution and advancement of information technologies, smart phone industry, multi-omic technologies, availability with 5G networks and emergence of big data era has greatly impacted on diagnostic, biomedical and e-healthcare sectors. Intelligent sensors, wearable, digital imaging, smart phone based diagnostic and connected networking provides smart approach and platform towards precision diagnostics. Recently, Internet of Things (IoT) have shown remarkable impact on diverge sectors such as digital imaging, smart sensing, digital diagnostic, digital biotech, telemedicine, precision farming, lab-on phone, smart home, smart city planning, smart retails and Research and Development (R&D) automation etc. Application of IoT technology in diagnostic and healthcare opens a way for personalization in the medical care depending on individual needs, additionally giving option for well-organized way for remote healthcare and management. This review focuses on theoretical, technological, advanced aspects of digital diagnostic utilizing IoT technology. Furthermore, we have also highlighted the opportunities and challenges for IoT in exploring the futuristic scope and innovation in diagnostic application. IoT based diagnostic, sensing and imaging devices provides unprecedented precision, automation in the diagnostic and thereby could significantly improve the biomedical and e-healthcare area.