Returning Int from If statement

I'm trying to make an int equal to a certain value if a condition is true. I'm having trouble getting the bloodtype int from the if statement so it can be applied to my class. I know its probably a simple solution but my brain is fried.

 private void btnAddPatient_Click(object sender, RoutedEventArgs e)////Add Patients
    {
        string name = txtPatientName.Text;
        int bloodType,age=30;           
        DateTime dob;
        bool bloodA = rbA.IsChecked.Equals(true);
        bool bloodB = rbB.IsChecked.Equals(true);
        bool bloodAB = rbAB.IsChecked.Equals(true);
        bool blood0 = rb0.IsChecked.Equals(true);




        // if (dpDOB.SelectedDate == null || txtPatientName.Text == ""||bloodType==0)
        if (dpDOB.SelectedDate == null || txtPatientName.Text == "" || !bloodA || !bloodAB || !bloodB || !blood0)
        {

            if (txtPatientName.Text == "")
            {
                MessageBox.Show("Please enter Patient's Name");
            }

            else if (!bloodA || !bloodAB || !bloodB || !blood0)
            {
                MessageBox.Show("Please enter patient's blood type");
            }

            //else if (dpDOB.SelectedDate == null)
            //{
            //    MessageBox.Show("Please select a date");
            //}

        }

        else
       if (bloodA)
        {
            bloodType = 0;

        }
        else if (bloodB)
        {
            bloodType = 1;
        }
        else if (bloodAB)
        {
            bloodType = 2;
        }
        else {             
            bloodType = 3;           

            dob = dpDOB.SelectedDate.Value;

            Patient patient= new Patient(name, age, bloodType);///cant get bloodtype value

            MainWindow mainWindow = Owner as MainWindow;

           patients.Add(patient);
            lstPatients.ItemsSource = null;
            lstPatients.ItemsSource = patients;
            // this.Close();
        }