Table 1.

Comparison of biological fluid suitability for various biomolecular sensing applications

Body fluid	Correlation with blood	Analyte diversity	Glucose lag time	Invasiveness	Body-based compatibility	Can be stimulated?
Urine	Medium	Low	Long	Low	Wearable	No
Blood	Not applicable	Very high	Not applicable	High	Implantable	No
Saliva	Low	Medium	15 min	Low	Wearable	Yes
Sweat	Medium	Low	10 min	Low	Wearable	Yes
Tears	High	Medium	13 min	Low	Wearable	Yes
Interstitial fluid	Very high	High	5–6 min	Medium	Wearable, implantable	No
Breath	Unknown	Low	Not applicable	Low	Wearable	Not applicable
Digestive fluid	Unknown	Medium	Not applicable	Medium	Consumable	Not applicable