private void CreateObxSegment()
{
var ourOrderObservation = _oruR01Message.GetPATIENT_RESULT().GetORDER_OBSERVATION();
var observationSegment = ourOrderObservation.GetOBSERVATION(0);
var obxSegment = observationSegment.OBX;
obxSegment.SetIDOBX.Value = "0";
//see HL7 table for list of permitted values here. We will use "Encapsulated Data" here
obxSegment.ValueType.Value = "ED";
obxSegment.ObservationIdentifier.Identifier.Value = "Report";
//"Varies" is a NHAPI class to handle data where the appropriate
//data type is not known until run-time (e.g. OBX-5)
var varies = obxSegment.GetObservationValue(0);
var encapsulatedData = new ED(_oruR01Message, "PDF Report Content");
encapsulatedData.SourceApplication.NamespaceID.Value = "Our .NET Application";
encapsulatedData.TypeOfData.Value = "AP"; //see HL7 table 0191: Type of referenced data
encapsulatedData.DataSubtype.Value = "PDF";
encapsulatedData.Encoding.Value = "Base64";
var base64EncodedStringOfPdfReport = _Base64Helper.ConvertToBase64String(new FileInfo(_pdfFilePath));
encapsulatedData.Data.Value = base64EncodedStringOfPdfReport;
varies.Data = encapsulatedData;
}