AFI- amniotic Fluid Index- is an ultrasound finding of BPP.
NST- a fetal heart Rate monitoring-( to measure fetal heart rate and to measureuterine contractions.Fetal movement, heart rate and “reactivity” of heart rate to movement is measured for 20-30 minutes.)
The biophysical profile (BPP) is a noninvasive test that predicts the presence or absence of fetal asphyxia and, ultimately, the risk of fetal death in the antenatal period.[1] When the BPP identifies a compromised fetus, measures can be taken to intervene before progressive metabolic acidosis leads to fetal death.
The BPP has become a standard tool for providing antepartum fetal surveillance. The BPP integrates 5 parameters to yield a biophysical profile score (BPS- A TOTAL SCORE OF TEN) and includes
(1) the nonstress test (NST),
(2) ultrasonographic measurement of the AFV,
(3)observation of the presence or absence of fetal breathing movements,
(4) gross body movements, and
(5) tone.
The BPP allows 2 points for each parameter that is present, yielding a maximum score of 10; however, if all of the ultrasonographic variable findings are normal, the FHR variable may be excluded, because no change is made in the predicative accuracy of the BPP by including the FHR.( here it is NST).
Usually the all other 4 factors except No1 ( ie NST) are determined by ultrasound technique, for a TOTAL OF 8 BPS; it is referred as 2/8, 4/8, 6/8 8/8of fetal welbeing, by the Ultrasound performing Physician.
If 1 or more of these ultrasonographic variable findings are abnormal, the NST should be performed again and with more frequency.
This makes sense about assigning code 76818- for fetal BPP; with NST.
76819- for fetal BPP without NST.
So, I hope it makes it clear that AFI is not NST and NST is not AFI.
Thank you.