Subclinical ketosis, a common metabolic issue in the transition period, is estimated to cost $78 per case due to decreased milk production, reduced fertility, displaced abomasum, and other health issues (Geishauser et al., 2001). Considering the potential loss of profit to a producer, this study focused on identifying the most effective monitoring program to identify at risk cows. Holstein (n = 54) and Jersey (n = 52) multiparous cows at a commercial dairy were enrolled during the prepartum period and then followed to approximately 21 DIM. Weekly blood samples were analyzed using Nova Max (Nova Diabetes Care Inc., Billerica, MA) for Glucose (Glu, mg/dL) and β-hydroxybutyric acid (BHB, mmol/L). Previous research has shown the meter to have a sensitivity of 74.4% and specificity of 100%. Weekly milk tests were taken in first 21 DIM and compared with BHB and Glu. Both breeds experienced a decrease in Glu and an increase in BHB from prepartum to postpartum (P < 0.0001). However, Jerseys were lower than Holsteins for both during early lactation with values of 2.45 mg/dL and 0.13 mmol/L, respectively (P = 0.061, P < 0.0001). Due to this difference, breeds were separated for the rest of analysis. Blood categories were assigned as 1 (less than) or 2 (greater than) for multiple thresholds for both BHBA and Glu levels. Initially, blood parameters were compared with health issue risk and milk production level individually, but neither alone yielded any significant results. Due to a low incidence of hyperketonemia, Jerseys did not have enough samples available for analysis; only 5 cows had >1.0 mmol/L BHB versus 25 Holstein cows. For Holsteins, using both parameters as markers were more accurate for identifying suppressed milk production. They had increased risk of health issues and a decrease of 5.44 kg/d of milk when BHB >1.0 mmol/L and Glu <50 mg/dL (P = 0.099). The highest incidence of ketosis for both breeds was in the first week of production. Therefore, a monitoring program within the first week of lactation would be more beneficial for Holsteins. Based on these results, both BHB and Glu testing is recommended. Because Glu strips are less expensive, Glu can be used to prescreen for hypoglycemia first, and then BHB can be used to confirm the diagnosis if Glu values are low.