Two new dual-core D-shaped SPR (surface plasmon resonance) PCFs (photonic crystal fibers) (DCD-S-SPR PCF) with a splitting barrier between the twin cores are proposed for the detection and sensing of the different bio-samples of human blood. Moreover, each proposed model is displaying a promising performance for different optical parameters, such as refractive index (RI), confinement loss (α_c) birefringence (B_i), coupling length (L_c), transmittance (T_x), wavelength sensitivity (S_w), amplitude sensitivity (S_a), resolution, and figure of merit (FOM). However, the observation is done by the finite element method (FEM) for the assumed wavelength range from 2.1 to 3 μm and provides the comparison between two DCD-S-SPR PCF models. The performance indicator measurements for model 1 and model 2 corresponding to the wavelength sensitivity, amplitude sensitivity, resolution, transmittance variance, FOM, and detection limit of each proposed DCD-S-SPR PCF are, respectively, as follows: 12,320.10 nm/RIU, − 230 RIU⁻¹, 1.5 × 10⁻² RIU, 4342.34 dB/RIU, 190, 0.21; and 18,550 nm/RIU, − 360 RIU⁻¹, 1.0 × 10⁻¹ RIU, 6071.42 dB/RIU, 250, 0.07. Also, the satisfactory results of those parameters of each hemoglobin sensor confirm the better sensing performance, and the hemoglobin sensor proves itself a tough competitor in the field of PCF-based bio-sensing application.