Rationale:

Hyperinsulinemia is an important issue in terms of the obesity epidemic sweeping the developed world. Measurement of insulin (INS) is critical to understanding the value of various interventions, however making large numbers of venous measurements is inconvenient.

Objective:

This study was designed to compare the INS responses in capillary and venous blood samples obtained simultaneously following various dietary interventions.

Methodology:

Volunteer subjects (age 22-33) (n = 10) had simultaneous capillary and venous blood samples drawn before and 60-min after ingesting either a regular (R) soft drink (both with and without caffeine (C)) or a diet (D) soft drink (both with and without C). Samples were analyzed for INS with ELISA.

Results:

Although there were some significant differences in absolute values of INS measured in capillary vs venous blood, pre to post changes in INS were very similar between C vs V (RCcap = 4.9 to 9.4 vs RCven = 5.7 to 9.9; RnoCcap = 4.6 to 7.1 vs RnoCven = 4.3 to 10.0; DCcap = 4.6 to 4.4 vs DCven = 5.4 to 4.5; DnoCcap = 4.6 to 4.4 vs DnoCven = 5.1 to 4.6). The combined capillary vs venous changes were well correlated (r = 0.91).

Conclusion:

Although there are slight differences in the absolute values of INS measured in capillary vs venous blood samples, the differences are well correlated (r = 0.91) and highly predictable (Ven INS = 0.53 + 0.976 Cap INS).