Finding a point in data with FIND - accommodate both increasing and decreasing data

Hello, I have data that I want to find the point closest to a threshold (th=800).

1728.00       1755.00       1778.00       1738.00       1810.00       1552.00       1274.00        924.00        668.00        407.00        202.00        132.00

then I use:

idx = single(find(data >= th, 1, 'last'));

However, sometimes the data is reversed so it would be 'first'.

idx = single(find(data >= th, 1, 'first'));

How can I accommodate both scenarios?

(For info, i then use this index to seed a more accurate value)

vq1 = interp1(line(yval-1:yval+1), x(yval-1:yval+1), th,'pchip');   % Interpolate In Region

[Jason]

But the data is randomly alternated, and I don't want to have to go into the code each time. I think I have done it with:

       diff=line-th   
       [~,idx] = min(abs(diff))

Answer 1

[Matt J]

 [~, idx] =min(abs(data - th));

[Jason]

Thanks