Pathology/Lab Coding Alert

Question: We received a vaginal fluid specimen for a Nitrazine smear. What is the test for, and how do we code it?

Illinois Subscriber

Answer: A physician may order a Nitrazine test on vaginal fluid to determine if a pregnant patients amniotic fluid is leaking. The test involves placing a drop of vaginal fluid on a paper strip containing Nitrazine dye. A chemical reaction causes a color change in the paper that indicates pH.

The normal pH of vaginal fluid is between 4.5 and 5.5, while the normal pH of amniotic fluid is much higher -- usually between 7.0 and 7.5.

You should report the test as 83986 (pH, body fluid, except blood). This is a waived test under the Clinical Laboratory Improvement Amendments (CLIA), so you should report the test with modifier QW (CLIA waived test) if your lab operates under a certificate of waiver.