OBJECTIVES: Existing guidelines recommend determination of RAS mutation status in patients with metastatic colorectal cancer (mCRC) as anti-epidermal growth factor receptor (anti-EGFR) therapies are ineffective in tumors with RAS mutations. The cobas® KRAS Mutation Test (cobas test) detects twelve mutations in KRAS exon 2 and seven mutations in exon 3, whereas the therascreen KRAS RGQ PCR Kit (therascreen test) detects seven overlapping mutations in KRAS exon 2. We estimated the potential clinical and economic impact of using the cobas test versus the therascreen test in all mCRC patients in Denmark. METHODS: A budget impact model was developed from the Danish healthcare perspective.  Model inputs were obtained/estimated from the literature (e.g. 1,260 annual mCRC cases were estimated). Treatment patterns were from Roche data on file. Sensitivity and specificity were assumed to be the same as positive percent agreement and negative percent agreement comparing to Sanger sequencing, which were 96.9% and 88.7% for cobas, 94.2% and 87.5% for therascreen. Drug and treatment-related costs were calculated from the national pharmaceutical procurement service (Amgros) and Danish national tariffs, respectively. The model calculated the average treatment cost for mCRC patients over 5 years, using median time on treatment and median overall survival.  Costs were presented in 2015 Euros (1 Euro = 7.46021DKK). RESULTS: Using the cobas test resulted in a reduction of 63 patient-months lost due to inappropriate care (avoiding anti-EGFR therapies in mutant patients) and an improvement in median overall survival.  Using cobas KRAS testing reduced the costs of inappropriate care by €991K and decreased monthly cost per patient by €3, while having a minor increase (€105K, 0.2%) in healthcare costs. CONCLUSIONS: Using the cobas test with better sensitivity and broader mutation coverage of KRAS was associated with a neutral budget impact and may improve patient outcomes by reducing the likelihood of receiving inappropriate care in mCRC patients.