Table 1. Sensitivities of current methods in malaria diagnosis.

Methods	Detection limit in the ring stage	Original statement without conversion
Giemsa stained microscopy	4 to 20 parasites/μl in thick smear	4 to 20 parasites/μl in thick smear for all different stages. The threshold may be higher in the field for the early stage4,5.
Flow cytometry	100000 parasites/μl	This technique is useful for a parasitemia level around 2% and maybe more helpful in a late stage12.
Magneto optical technology (MOT) using polarized light	10000 parasites/μl*	0.002% parasitemia level in the trophozoite stage6.
Quantitative Buffy Coat (QBC) Test	1000 parasites/μl	The sensitivity will be lower than 30% when the parasitemia level is lower than 1000 parasites/μl11.
Rapid diagnostic tools (RDTs)	100 to 500 parasites/μl for P. falciparum infection	100 to 500 parasites/μl for P. falciparum infection in all different stages4,52.
Cell dyn machine	27.786 parasites/μl (in unknown stages)	The parasitemia level of clinical samples varies from 320 to 285714 parasites/ml with an average of 27786 parasites/ml, using Cell dyn 37005.
Laser desorption mass spectrometry (LDMS)	10 parasites/μl	10 parasites/μl in the ring stage7.
Micromagnetic Resonance Relaxometry (MRR)	10 parasites/μl for P. falciparum infection	0.0002% parasitemia level for P. falciparum infection mostly in the ring stage and 0.0001% for P. berghei mouse model19.
Polymerase Chain Reaction (PCR)	around 0.7 parasites/μl for P. falciparum infection	Real-time PCR assay shows a detection limit of 0.7, 4, and 1.5 parasites/μl for P. falciparum, P. vivax, and P. ovale, respectively in different stages9,10.
Attenuated total reflectance infrared spectroscopy (ATR-IR)	0.5 parasites/μl	The absolute detection limit was found to be 0.00001% parasitemia in the ring stage15.
Surface enhanced Raman spectroscopy (SERS) using butterfly-wing nanostructures	25 parasites/μl	0.0005% parasitemia level in the ring stage33.
Method 1 in our study	500 parasites/μl	0.01% parasitemia level in the ring stage.
Method 2 in our study	2.5 parasites/μl	0.00005% parasitemia level in the ring stage.

The percent parasitemia level is converted to the number of parasites per microliter with the assumption that normal blood in human body contains 5 × 10⁹ RBCs/ml.

^*The detection limit of the MOT method was converted from the hemozoin concentration⁶ to the parasitemia level in the original paper. Their assumptions in conversion included: A) hemoglobin concentration in a healthy human is around 340 g/l; B) parasites in the trophozoite stage convert 50% of hemoglobin to hemozoin and then yield around 0.6 pg hemozoin per cell. The detection limit of 0.06 μg/ml in hemozoin concentration was converted to a parasitemia level of 100 parasites/μl in the trophozoite stage⁶. For consistency with all other techniques, the parasitemia level in the trophozoite stage is converted to that in the ring stage here for the same hemozoin concentration based on the assumption that hemozoin concentration in the trophozoite stage is 100 times that in the ring stage⁵³,⁵⁴. This yields a sensitivity of 10000 parasites/μl in the ring stage for MOT.