What is the fastest way to detect an invalid triangle in a 3D Mesh?

With invalid I mean:

• zero area
• three collinear points
• two overlapping points

We currently use this - very slow - approach:

Code :
    if (Area(p1,p2,p3) < 1e-3)
 
         Debug.WriteLine("Invalid triangle found!");
 
    public double Area(Point p1, Point p2, Point p3)
    {
 
        double[,] m = new double[3, 3];
 
        m[0, 0] = p1.Y; m[0, 1] = p1.Z; m[0, 2] = 1;
        m[1, 0] = p2.Y; m[1, 1] = p2.Z; m[1, 2] = 1;
        m[2, 0] = p3.Y; m[2, 1] = p3.Z; m[2, 2] = 1;
 
        double det1 = Matrix.Determinant3(m);
 
        m[0, 0] = p1.Z; m[0, 1] = p1.X; m[0, 2] = 1;
        m[1, 0] = p2.Z; m[1, 1] = p2.X; m[1, 2] = 1;
        m[2, 0] = p3.Z; m[2, 1] = p3.X; m[2, 2] = 1;
 
        double det2 = Matrix.Determinant3(m);
 
        m[0, 0] = p1.X; m[0, 1] = p1.Y; m[0, 2] = 1;
        m[1, 0] = p2.X; m[1, 1] = p2.Y; m[1, 2] = 1;
        m[2, 0] = p3.X; m[2, 1] = p3.Y; m[2, 2] = 1;
 
        double det3 = Matrix.Determinant3(m);
 
        return Math.Sqrt(det1 * det1 + det2 * det2 + det3 * det3) / 2;
 
    }

Thanks,

Alberto