teeter, titer

Teeter or teeter means to wobble or to move unsteadily--
The cart will teeter with a flat tire, but it should still do the job.
Their little girl likes to teeter around the house in an old pair of high heels.

Titer or titer ( most commonly pronounced to rhyme with teeter ) means a measure of the strength of a chemical in a solution, most commonly used as a test of the quantity of an antibody, to determine if a person is immune to a particular disease--
A titer can show us that he's already had the disease, or that he's been vaccintated for it.
We'll need a titer to find out if he's immune to the measles.

Now that you know that, you can say--
"The doctor wants a titer for polio, to find out if that's what makes him teeter when he walks."

Note--"titer" , meaning a measure of antibodies, is sometimes pronounced to rhyme with "tighter", meaning more tense, taut, or firmly fixed--
Tie the laces tighter, so they won't come undone.
Note# 2--"titter" means to laugh in a silly or affected way--
If I have to listen to that mindless titter of his one more time, I may lose my temper.