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Version: v0.1.9

Read lab results, orders and timing

This guide reads an observation result (ORU^R01): the results, the orders they answer, and the timing an order or medication carries.

Read every result​

msg.observations() returns every OBX in document order, whether or not an OBR groups it. The coded fields are CWE composites: identifier is the code and text the name.

import { parseHL7 } from "@cosyte/hl7";

const raw = [
  "MSH|^~\\&|LAB|MAIN|EHR|REF|20260419143000||ORU^R01^ORU_R01|EX00002|P|2.5",
  "PID|1||MRN67890^^^HOSP^MR||Doe^Alice^B||19750620|F",
  "OBR|1|ORD-EX-1|FLR-EX-1|CBC^Complete Blood Count^L|||20260419140000",
  "OBX|1|NM|WBC^White Blood Cells^LN||7.5|10*3/uL|4.5-11.0|N|||F",
  "OBX|2|NM|HGB^Hemoglobin^LN||11.9|g/dL|12.0-16.0|L|||F",
  "OBX|3|ST|COMMENT^Comment^L||Specimen slightly hemolyzed||||||F",
].join("\r");

const observations = parseHL7(raw).observations();

observations.length; // => 3

const [wbc, hgb, comment] = observations;
wbc?.identifier.identifier; // => "WBC"
wbc?.identifier.text; // => "White Blood Cells"
wbc?.value; // => 7.5
wbc?.units?.identifier; // => "10*3/uL"
wbc?.referenceRange; // => "4.5-11.0"
hgb?.abnormalFlags; // => "L"
hgb?.status; // => "F"
comment?.value; // => "Specimen slightly hemolyzed"

An observation's value takes its type from OBX-2: NM is a number, SN a structured numeric, TS and DT a fidelity TS, CWE and CE a composite, and every other type a string. status is OBX-11 exactly as sent; resultStatus classifies it (see Result status classification).

Group results under their order​

msg.orders() returns one entry per OBR, each with the OBX segments that follow it; an ORC just before an OBR gives that order its orderControl. An OBX before the first OBR is in observations() but in no order. Use orders() when a result has to stay with the order that requested it.

import { parseHL7 } from "@cosyte/hl7";

const raw = [
  "MSH|^~\\&|LAB|MAIN|EHR|REF|20260419143000||ORU^R01^ORU_R01|EX00003|P|2.5",
  "PID|1||MRN67890^^^HOSP^MR||Doe^Alice^B",
  "OBR|1|ORD-EX-1|FLR-EX-1|CBC^Complete Blood Count^L",
  "OBX|1|NM|WBC^White Blood Cells^LN||7.5|10*3/uL|4.5-11.0|N|||F",
  "OBR|2|ORD-EX-2|FLR-EX-2|BMP^Basic Metabolic Panel^L",
  "OBX|1|NM|GLU^Glucose^LN||120|mg/dL|70-99|H|||F",
  "OBX|2|NM|NA^Sodium^LN||140|mmol/L|135-145|N|||F",
].join("\r");

const orders = parseHL7(raw).orders();

orders.length; // => 2
orders[0]?.placerOrderNumber; // => "ORD-EX-1"
orders[1]?.universalServiceId?.text; // => "Basic Metabolic Panel"
orders[1]?.observations.map((o) => o.identifier.identifier); // => ["GLU", "NA"]

Read an order's timing​

Every order and every medication carries timings: the TQ1 segments (HL7 v2.5 and later), or the legacy timing embedded in ORC-7 or RXE-1 when no TQ1 is present.

import { parseHL7 } from "@cosyte/hl7";

const raw = [
  "MSH|^~\\&|PHARM|MAIN|EHR|REF|20260419143000||RDE^O11^RDE_O11|EX00004|P|2.5",
  "PID|1||MRN67890^^^HOSP^MR||Doe^Alice^B",
  "ORC|NW|ORD-EX-9",
  "TQ1|1||Q6H||||20260419150000|||||||24",
  "RXE||00000-0000-00^Example tablet^NDC|500||mg",
].join("\r");

const med = parseHL7(raw).medications()[0];
const timing = med?.timings[0];

timing?.source; // => "TQ1"
timing?.repeatPattern?.code; // => "Q6H"
timing?.repeatPattern?.kind; // => "parametric"
timing?.repeatPattern?.interval; // => { count: 6, unit: "H" }
timing?.totalOccurrences; // => 24
timing?.startDateTime?.raw; // => "20260419150000"

The repeat pattern is surfaced as sent. The library never resolves Q6H to clock times or maps it to another frequency: reading Q6H as daily, or losing a BID, changes the number of doses given. kind records only how the code is written. Order and medication timing has the field map and what is out of scope.

Reference​