In this paper, a novel partial type-b crystalline core with more compact cladding in hexagonal packing photonic crystal fiber (CC-PCF)-based optical sensor has been proposed for sensing different blood components. This fiber has investigated in terahertz (THz) region from 1.5 to 3.50 THz, intending to superior relative sensitivity with low confinement loss (CL). Circular air holes have been employed in the formation of the partial type-b crystalline core in a symmetric manner. A significant relative sensitivity response of 80.93%, 80.56%, 80.13%, 79.91%, and 79.39% are achieved for the targeted analytes such as RBCs, hemoglobin, WBCs, plasma, and water at frequency <inline-formula> <tex-math notation="LaTeX">${f} = 1.5$ </tex-math></inline-formula> THz. In X-polarization mode, a negligible CL of <inline-formula> <tex-math notation="LaTeX">$1.23\times 10^{-11}$ </tex-math></inline-formula> dB/m, <inline-formula> <tex-math notation="LaTeX">$8.63\times 10^{-12}$ </tex-math></inline-formula> dB/m, <inline-formula> <tex-math notation="LaTeX">$4.93\times 10^{-12}$ </tex-math></inline-formula> dB/m, <inline-formula> <tex-math notation="LaTeX">$2.93\times 10^{-12}$ </tex-math></inline-formula> dB/m, and <inline-formula> <tex-math notation="LaTeX">$1.13\times 10^{-12}$ </tex-math></inline-formula> dB/m are also gained, respectively, for same analytes and at same THz frequency. Moreover, effective area (<italic>A</italic>_eff), V-Parameter (<inline-formula> <tex-math notation="LaTeX">$V_{\mathrm{ eff}}$ </tex-math></inline-formula>), dispersion (<inline-formula> <tex-math notation="LaTeX">$\beta _{2}$ </tex-math></inline-formula>), spot size (<inline-formula> <tex-math notation="LaTeX">$W_{\mathrm{ eff}}$ </tex-math></inline-formula>), and beam divergence (<inline-formula> <tex-math notation="LaTeX">$\theta $ </tex-math></inline-formula>) have been determined over the investigated region. The improved outcomes are anticipated that the proposed CC-PCF sensor will be opened a new epoch in biomedical sensing purposes