Health Information Management

Fetal non-stress tests represent important part of maternal and fetal health

JustCoding News: Outpatient, January 11, 2012

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by Lori-Lynne A. Webb, CPC, CCS-P, CCP, COBGC, CHDA

The ultimate goal of fetal surveillance is to prevent fetal death. Part of this process is a fetal non-stress test (FNST), the monitoring of the fetal heart rate in response to fetal movement (CPT® code 59025).

The healthcare provider auscultates the fetal heart rate using an external electronic monitor attached to the pregnant patient. The FNST is a noninvasive testing procedure. The testing machine itself uses two separate leads connected to the testing unit and a monitoring ‘belt’ that is placed upon the pregnant patient that includes the ultrasound probe and a pressure transducer.

Performing an FNST

The ultrasound probe transmits the fetal heart rate in beats per minute (bpm), which the testing machine records via a non-stress testing grid/strip. Each small vertical square represents 10 beats. Each small horizontal square represents 10 seconds, while each large horizontal square is one minute.

The pressure transducer transmits the pressure generated by uterine contractions in mm Hg. Each small vertical square represents 5 mm Hg. Each small horizontal square represents 10 seconds, while each large horizontal square is one minute.

Physicians perform NFST for a variety of reasons and diagnoses. The following list details some of the most frequent diagnoses for performing the FNST.

  • Gestational hypertension
  • Gestational diabetes
  • Decreased fetal movement
  • Fetal tachycardia or bradycardia
  • Vaginal bleeding or spotting
  • Pre-eclampsia (e.g., headache, visual symptoms)
  • Intra-uterine growth retardation (IUGR)

Once the physician decides to perform the test, the staff members position the patient on a bed or table, and then apply the external fetal monitors. The monitors record fetal heart rate and fetal movements. Physicians review and interpret the tracing and laboratory reports and document their findings in the patient’s record. Physicians then provide instructions for the patient and her family.

Coding NFST

Coders need to know what is and is not only included in the procedure and process of the test. Providers must also meet clinical documentation requirements. CMS bundles the FNST with fetal ultrasound codes 76815, 76818, and 76819. CMS also bundles urinary catheterization codes 51701 and 51702 with code 59025. FNST service has zero global days attached, which is good news when coders need to report a FNST on consecutive days.

The FNST code 59025 can be billed as a global service, as interpretation only (modifier -26), or as a technical component only (modifier -TC). Another unusual coding guideline for a FNST is for multiple gestations or fetuses. Each fetus is recorded and the provider can separately document and interpret the procedure for each fetus tracing and record.

Interpreting fetal heart rate tracings

The interpretation of the fetal heart rate record tracing should follow a systematic approach with a full qualitative and quantitative description of the following:

  • Fetal baseline rate
  • Baseline fetal heart rate (FHR) variability
  • Presence of FHR accelerations
  • Periodic or episodic FHR decelerations
  • Changes or trends of FHR patterns over time (e.g., 10 minutes, 20 minutes, one hour, three hours, etc.)
  • Frequency and intensity of uterine contractions

The baseline FHR is the fetal heart rate during a 10-minute session and should be rounded to the nearest 5 bpm increment. Providers should exclude periods of marked FHR variability, periodic or episodic changes, and segments of baseline that differ by more than 25 bpm. The minimum baseline duration must be at least two minutes. If minimum baseline duration is less than two minutes then the baseline FHR is considered indeterminate.

Physicians commonly note reactivity in the FNST documentation. An FNST is considered reactive when two or more fetal heart rate accelerations peak (but do not necessarily remain) at least 15 bpm above the baseline and last 15 seconds from baseline to baseline within a 20-minute period with or without fetal movement discernible by the maternal patient.

Knowing FNST terms

Terms that are also found within the FNST documentation include:

  • Episodic patterns: Patterns not associated with uterine contractions.
  • Periodic patterns: Patterns associated with uterine contractions. With some exceptions, early and late decelerations are periodic. Variables can also be periodic.
  • Duration: Quantified in minutes and seconds from the beginning to the end of the deceleration or acceleration.
  • Early deceleration: Occurs with the peak of a contraction.
  • Late deceleration: Occurs after the peak of a contraction and lasts more than 30 seconds.
  • Variable deceleration: Noted when the deceleration lasts greater than 15 seconds but less than two minutes.
  • Prolonged deceleration: Noted when a decrease of the FHR lasts more than two minutes but less than 10 minutes.

FNST documentation requirements

The clinical FNST documentation needs to include four elements to be coded and billed.

  1. Clinical indication, for example decreased fetal movement, IUGR, etc.
  2. Interpretation, for example fetal heart tones (FHT) show a baseline of 130 bpm with 10x10 accelerations and moderate variability, reactive with no decelerations.
  3. Time noted, for example that a patient was monitored for a certain number of minutes or hours through the course of the stay.
  4. Signature and authentication.

All payers require the provider to sign the documentation and interpretation.

Coding considerations

When coding, the bill date should be the same as the date the physician performed the FNST. If the physician interprets the test on a different date than the FNST test itself, then bill interpretation only on the date the physician performed the interpretation. Remember to verify the place of service, for example:

  • In the office (pos 11)
  • Outpatient hospital (pos 22)
  • Inpatient hospital (pos 21)
  • Emergency department (pos 23)

When coding for multiple babies, code the global service for the multiple fetuses as:

  • Code 59025 for Baby A
  • Code 59025-59-51 for Baby B

Code the interpretation only of the FNBT for multiple fetuses as:

  • Code 59025-26 for Baby A
  • Code 59025-26-59-51 for Baby B

However, you can bill one technical component, regardless of the number of fetuses present. The provider needs to document separately identifiable interpretations for each baby denoted in the record to bill the FNST codes for multiples.

Sample FNST documentation

Consider the following sample FNST documentation.

DATE OF SERVICE: 11/11/2011.

SUBJECTIVE: Ms. L is a 35-year-old gravida 5, para 3, white female patient of Dr. Hero at 36-4/7 weeks' gestation who presents complaining of uterine contractions. They are anywhere from 4–10 minutes apart and are mild to moderate. She denies any leaking fluid or ruptured membranes or bleeding. She has had no problems with this pregnancy except that her blood pressure has been running somewhat high throughout her pregnancy with systolics in the 140s on numerous occasions.

VITAL SIGNS: Afebrile, vital signs stable.
GENERAL: The patient is a well-developed, well-nourished, female in no acute distress.
ABDOMEN: Soft. Non-tender.
PELVIC: Cervix is very posterior, -2 station, 50% and tight 2 cm, unchanged after walking for an hour.

FNST: Fetal heart tones show moderate variability, 15 x 15 accelerations and no decelerations with a baseline of 145 bpm. Uterine contractions are present about every 4–6 minutes. Patient was observed and recorded over the course of 60 minutes.

ASSESSMENT: False labor in a multiparous patient at 36-4/7 weeks' gestation. Fetal status reassuring.

PLAN: Patient was given labor instructions. She will be calling Dr. Hero's office later in the day to get a refill on her Norco and Fioricet. She does not want anything else from us now.

Editor’s note: Lori-Lynne Webb, CPC, CCS-P, CCP, is an independent consultant in Melba, ID. E-mail her at or

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