Understanding Test Indications Can Simplify Coding for Antepartum Fetal Assessments
Published on Sat Aug 01, 1998
Antepartum fetal stress testing can be a difficult area for many ob/gyn coders. Choosing the correct diagnosis code and matching CPT code often necessitates an in-depth understanding of the indications for these tests. In addition, some of these tests are not a routine part of antepartum care and, as such, require additional documentation of medical necessity. Recently OCA has received several questions from subscribers seeking clarification on the differences between, and correct coding for, antepartum fetal testing, including the contraction stress test (59020), fetal nonstress test (59025), and the fetal biophysical profile (76818).
These tests are common antepartum fetal assessments that belong to a group of tests used to identify a fetus at risk. According to Fundamentals of Gynecology and Obstetrics by Dale Russel Dunnihoo, MD, PhD (J.B. Lippincott Company, 1990), these tests are based on the premise that a fetus with a low fetal reserve (i.e., in poor condition) may be in danger of experiencing distress during the course of pregnancy and, particularly, during the course of labor. The status of the fetus can be evaluated by observing how it reacts during contractions (which produce stress). The physician monitors fetal vital signs, movement, fetal tone, amniotic fluid volume and the arterial blood flow.
These three tests require evidence of medical necessity. They would usually be ordered when a pregnancy is at increased risk for antepartum fetal demise.
1) Contraction Stress Test (CST)
Dunnihoo points out that the CST is based on the premise that, during a contraction, oxygenation of the fetus will decrease and create a situation of stress for the fetus. The obstetrician is interested in monitoring the fetal heart rate and seeing how quickly the fetus recovers from the stress of the contraction. If the fetus does not have much respiratory reserve it will experience late deceleration of the fetal heart rate (FHR). In patients who have a lower than normal volume of amniotic fluid, cord compression may occur during the contraction which causes a variable pattern of heart rate deceleration.
Coders should note that the contraction stress test (59020) is distinct and separate from other fetal testing. If it is performed before or after other tests, the coder must ensure that medical necessity is clearly documented. The contraction stress test is also a CPT starred procedure. According to CPT guidelines this means that it does not have a predetermined package of pre- or post-operative services. An evaluation and management (E/M) service for an established patient would not normally be reported in addition to this procedure, unless the documentation clearly noted that the E/M service was significant and separately identifiable. The separately identifiable E/M service would be denoted by adding a modifier -25 (significant, separately identifiable E/M service by same physician [...]
