Question:
How can we use HL7Spy to find the last set of known allergies for each patient in a set of messages?
Answer:
The best way is to write a custom function that remembers the last set of allergies for each patient. Then in the OnFinished function we print out all patients with their last set of known allergies.
string _fileName = @"c:\temp\_test.txt";
Dictionary<string,Patient> _data = new Dictionary<string,Patient>(10000);
public class Patient
{
public Patient(string patientId)
{
Allergies = new HashSet<string>();
PatientId = patientId;
}
public HashSet<string> Allergies;
public string PatientId;
}
public override void Run() {
// Get an HL7 Message in parsed format
HL7Message message = GetParsedMessage();
MSH msh = message.Segments.First<MSH>();
if(msh==null || msh.MessageType_09.TriggerEvent_02.Value!="A08")
return; // not an ADT^A08 message
PID pid = message.Segments.First<PID>();
if(pid==null)
return; // no pid segment
List<AL1> patientAllergies = message.Segments.OfType<AL1>();
if(patientAllergies.Count==0)
return; // no allergies
string patientId = pid.PatientIdentifierList_03.First.ToString();
Patient pat;
if(!_data.TryGetValue(patientId,out pat))
{
pat = new Patient(patientId);
_data.Add(patientId,pat);
}
pat.Allergies.Clear();
// loop through all AL1 segments
foreach(AL1 al1 in patientAllergies)
{
pat.Allergies.Add(al1.AllergenTypeCode_02.ToString());
}
}
// Called once after the last message has been processed.
// It is a good place to perform cleanup and to report information.
// Always called from the UI thread.
public override void OnFinish()
{
// to figure out the distribution of all allergies
Dictionary<string, int> allergies = new Dictionary<string,int>(1000);
// write the data out to a file
using(System.IO.StreamWriter wr = new System.IO.StreamWriter(_fileName))
{
wr.WriteLine("Patient ID vs Allergy for {0} patient samples",_data.Count);
wr.WriteLine();
foreach(Patient p in _data.Values.OrderByDescending(p=>p.Allergies.Count))
{
wr.Write(p.PatientId);
wr.Write(',');
wr.Write(p.Allergies.Count);
foreach(string s in p.Allergies)
{
wr.Write(',');
wr.Write(s);
// calculate the total number of allergy types for the given set of patients
int frequency=0;
if(!allergies.TryGetValue(s,out frequency))
{
allergies.Add(s,1);
} else {
allergies[s]=++frequency;
}
}
wr.WriteLine();
}
wr.WriteLine();
wr.WriteLine();
wr.WriteLine("Allergy distribution for {0} patient samples.",_data.Count);
wr.WriteLine("Number of distinct allergies is {0}.",allergies.Count);
wr.WriteLine();
foreach(KeyValuePair<string,int> d in allergies)
{
wr.Write(d.Key);
wr.Write(',');
wr.Write(d.Value);
wr.WriteLine();
}
}
// launch notepad to display the file.
System.Diagnostics.Process.Start("Notepad",_fileName);
}