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The most widely implemented version of the NCPDP SCRIPT standard, 10.6, builds on the success of e-prescribing by enhancing certain data segments, one of which is the Observation (OBS) segment. OBS allows prescribers to use the e-prescribing transaction to transmit patient data such as height, weight, and diastolic and systolic blood pressure, which is data that has a significant impact on safe prescribing practices, particularly for pediatric patients. In this roundtable conversation, moderated by ComputerTalk‘s Will Lockwood four experts offer some background on the OBS segment and how it’s being put to use within both prescriber and pharmacy practice.

The Experts

Ajit Dhavle, Pharm.D., M.B.A.

VP of Clinical Quality


Matt Moore, M.B.A., C.Ph.T., P.M.P.

Senior Strategist


Kevin Johnson, M.D., M.S.

Cornelius Vanderbilt Professor

Chair of Biomedical Informatics

Professor of Pediatrics

Chief Informatics Officer

Vanderbilt University Medical Center

Christian Tadrus, Pharm.D., R.Ph., FASCP, AE-C

Sam’s Health Mart Pharmacies

Moberly, Mo.

CT: First, let’s hear more about just what the Observation segment is.

Ajit Dhavle: The Observation segment is part of the NCPDP SCRIPT version 10.6. Even though the SCRIPT version 10.6 is widely implemented by the e-prescribing industry today, the OBS segment is not always used. The OBS segment enables the transmission of additional pertinent patient information like the patient height, weight, and blood pressure in a structured format. It is recommended that the most recent patient height, weight, and blood pressure data be sent to the pharmacy along with the corresponding dates associated with these measurements.

CT: So this is not a segment that’s required when sending an e-prescription?

Dhavle: Although currently SCRIPT 10.6 does not mandate the inclusion of the segment, it is recommended that prescribers and their technology vendors regularly populate the data elements within the OBS segment and then include this segment in the electronic new and renewal prescriptions that they transmit to the pharmacy. The transmission of the OBS segment is especially important for infused, injected, oncology, and pediatric medications.

CT: What’s a good resource for those who want to learn more about the best practices for making use of the OBS segment?

Dhavle: The NCPDP SCRIPT Implementation Recommendations document [sections 3.7 and 3.8] includes detailed guidance complete with examples to help e-prescribing and EHR technology vendors implement the OBS segment.

CT: Kevin, let’s talk more about why consistent use of the OBS segment is critical for safe prescribing.

Kevin Johnson: The OBS segment is perhaps the most vital segment for validating the safety and appropriateness of pediatric prescriptions and prescriptions with highly variable dosing amounts. The role that pharmacists can play in improving the safety of the medication delivery system has been well described by the Institute of Medicine in the book Preventing Medication Errors, as well as in the medical literature. Pharmacists have the ability to use their information systems to ensure that patients have no allergies, but rely on data included with the prescription, such as indication, height, weight, and mg/kg dosing strategy, to check that the dosing is accurate and appropriate for indication. Because average patient weights range from 3.5kg in full-term newborns to 70kg in 20-year-olds, simply reviewing the dosing strategy and the final prescribed dose are insufficient for the pharmacy to verify that the child is receiving a proper amount of a medication.

Of course, it will take partnership from prescribers, e-prescribing system vendors, pharmacists, and patients to improve medication safety. Prescribers need to record accurate and codified information in EHRs that can be used to populate the OBS segment and other fields in e-prescribing systems (such as allergies or other medications). E-prescribing systems need to provide the level of usability to ensure accurate data entry, but also to allow prescribers a window into what will appear on the script, so that errors may be caught upstream. Pharmacists need to have interoperable systems that support electronic transfer of SCRIPT messages into their pharmacy system, and they need to review these data with patients prior to dispensing medications. They also need to teach the patient how to deliver the medication safely, without assuming that the family member understands how to measure the volume of a liquid medication, for example. Patients and families are the glue to this process, and need to provide accurate information about medication history, allergies, and questions related to dosing the medication.

CT: Matt, in light of the OBS segment’s importance and the fact that it’s not currently mandated by the standard, how is it being incorporated into prescriber software systems?

Matt Moore: In today’s sophisticated EHRs [electronic health records], and with potentially complex patient situations, the applicable patient weight to transmit in the electronic prescription can be surprisingly challenging. EHR vendors may need to build rules into their systems to determine which weight recorded in their system is the appropriate one to send. Rules may also need to be built to determine for which patients the weight will be sent and in what circumstances. But once these questions are answered, the mechanics of sending the data in the Observation segment are very straightforward. There is no ambiguity in the SCRIPT standard.

CT: So it’s really a matter of system vendors creating the right system support for this segment?

Moore: Comprehensive clinical decision support is baked into most EHRs these days. So any dangerous or inappropriate dosing should be caught on the provider side. But transmitting the patient weight, which may have been used to arrive at the prescribed dose, provides an opportunity for the pharmacist to do one final sanity check and hopefully catch a potentially dangerous situation that may have slipped through the cracks.

CT: Christian, what about at the pharmacy?

Christian Tadrus: It’s important that this sort of data be sent to the dispensing pharmacy system, as pharmacists have a corresponding liability to review dosing for every order they dispense. Upstream dose-checking is desirable and helps to reduce risk, but it really needs to be a robust, core function of the pharmacy dispensing system as well.

Also, age, weight, gender, and disease states of the patient are all factors in determining the appropriateness of a dose. For example, children grow faster than adults, male dosing calculations are different from those for a female, the elderly often respond differently to normal doses of some medications, cancer can affect metabolism, and diseases that affect the kidney and liver impact how the drug is eliminated from the body. Unless the pharmacy dispensing system possesses this information and presents it within the workflow in an efficient manner, pharmacists can’t do their job very effectively. As the medication experts, that’s unacceptable.

CT: What are the best practices for ensuring that OBS segment data is incorporated into the dispensing process in an actionable manner for pharmacists?

Tadrus: Ultimately, the pharmacist must be able to make an informed and clinically relevant decision quickly from within the typical workflow process. Vendors may choose to implement OBS segment data in various ways, but ideally should do so in a manner that ensures that pharmacists must view it and sign off on it as part of their process. While mandatory review can be burdensome, it helps drive accountability, so it’s important that vendors define a process that presents as much relevant information as possible in a manner that encourages utilization and efficient decision-making. Storing OBS segment data as it arrives in the patient record can also support clinical care activities.

Ideally, presentation of OBS segment data should occur at the earliest possible moment in the dispensing process — e.g., within prescription intake queues or during data entry steps — to help provide the maximum amount of time to review and resolve concerns. As OBS segment data can change over time, vendors should implement logic to alert the pharmacist to how current the information being presented is and when there are significant changes from previous periods. This can help identify the need for education or monitoring, and even drive engagement in other patient care services.

While the receipt and display of OBS segment data should be a minimum expectation — especially with respect to dosing in pediatric patients — that data alone is often not enough to make an informed decision as to the appropriateness of dosing when other factors impacting the patient are considered. So vendors might want to consider augmenting the OBS segment data presented to the pharmacist from other sources, to help the pharmacist properly interpret dosing within of the patient’s overall situation and identify discrepancies between prescriber and pharmacist records. Examples might include data created or assimilated through a pharmacist’s patient care activities or from other sources such as clinical therapy reference compendia or SNOMED and ICD-10 codes. While less sophisticated systems might be limited to simply displaying such information, more advanced systems might be able to provide a complete risk-based assessment of the patient. CT