Nursing flowsheets contain discrete and detailed patient data that can be reused in various clinical decisions including patient acuity estimation. To be reused, patient data should be represented consistently and unambiguously with standardized terminologies. This study investigated the domain completeness of SNOMED-CT toward the ICU nursing flowsheets and the acuity indicators used at Mayo Clinic. We first paraphrased the terms and the semantic relations appeared in the source materials into short clinical statement. Then, the entire prepared statement was mapped to SNOMED-CT and validated by expert reviewers. SNOMED-CT provided complete matches and partial matches to 78.13% and 14.1% of the flowsheets statements respectively. It provided complete matches and partial matches to 60.8% and 39.2% of the acuity statements respectively. The average observed agreement among the reviewers ran around 85%. Lack of appropriate terms was the major cause of the incomplete matches with the flowshee statements. Majority of the incomplete matches with the statements from the acuity indicators were caused by limitations in the concept models.