Workflows

Ask-at-order-entry (AOE)

Ask-at-order-entry (AOE) questions are test-specific data points the lab needs to interpret a result, such as gestational age for prenatal screens, current medications for drug-monitoring panels, the specimen source for microbiology, and so on. AOEs are submitted as part of the order's test_codes[].aoes array.

This page covers the test types with their own order-entry rules: Medical Drug Monitoring (PAIN), maternal serum (CMBP), microbiology, and histology/pathology. Histology and pathology orders also need the specimen's body site, which is sent on the specimen rather than as an AOE.

Medical Drug Monitoring (PAIN AOE)

Used for compliance/drug-of-abuse monitoring orders (e.g., test code 790600). The PAIN AOE captures patient medication context and a sequence number.

Required fields

For each medication using RXNorm values: PMSNUM, PMCODE, PMTEXT, PMSRCE, PMNOMP, PMPINP, PMPMLP, PMPMSF
For each medication using free text: PMSNUM, PMFTDN, PMNOMP, PMPINP, PMPMLP, PMPMSF

Rules

Exactly one of PMNOMP, PMPINP, PMPMLP, PMPMSF must be Y; the other three must be N.
Do not include duplicate medications, since duplicates cause an error.
RXNorm values are maintained by the US National Library of Medicine.

Example: patient has no medications

Code
{
  "id": "790600",
  "name": "COMPLIANCE DRUG ANALYSIS, UR",
  "aoes": [
    { "id": "PMSNUM", "text": "SEQUENCE NUMBER", "responses": [{ "value": "1", "label": "1" }] },
    {
      "id": "PMNOMP",
      "text": "NO MEDICATION USE",
      "responses": [{ "value": "Y", "label": "YES" }]
    },
    {
      "id": "PMPINP",
      "text": "MEDICATION LIST NOT PROVIDED",
      "responses": [{ "value": "N", "label": "NO" }]
    },
    {
      "id": "PMPMLP",
      "text": "PATIENT MEDICATION LIST PROVIDED ON REQUISITION",
      "responses": [{ "value": "N", "label": "NO" }]
    },
    {
      "id": "PMPMSF",
      "text": "PATIENT MEDICATION LIST PROVIDED ON SEPARATE FORM",
      "responses": [{ "value": "N", "label": "NO" }]
    }
  ]
}

The full reference includes a downloadable PDF with JSON examples for every patient-medication scenario; see Resources.

Maternal serum (CMBP first & second trimester)

Maternal serum AOE questions support prenatal AFP and integrated/sequential screens. Required entries cover gestational dating, sonographer credentials, prior screening history, chorionicity (twins), donor egg, and more.

Gestational dating

Submit exactly one gestational method per order:

Last menstrual period (LMP) date
Estimated date of delivery (EDD/EDC)
Weeks-and-days on date (NN weeks N days)
Decimal weeks (NN.N)

For calculation methods, the dating hierarchy, and decimal-week conversions, see the CMBP Maternal Serum Question Set and Test Cases document.

Test codes covered

017500, 017100, 017170, 017700, 017319, 010801, 451931: the order codes used in the 8 CMBP test cases.

Order codes by group

The required order-entry fields depend on the test code's group: Group 1 is maternal serum testing with nuchal translucency (NT), Group 2 is maternal serum screening without NT, and Group 3 is amniotic fluid or AFP. Labcorp recommends building all of the fields, since maternal serum screening requirements change over time.

Group	Order code	Test
Group 1 (MSSNT)	`017500`	1st Trimester w/NT
Group 1 (MSSNT)	`017100`	Integrated 1
Group 1 (MSSNT)	`017170`	Integrated 2
Group 1 (MSSNT)	`017700`	Sequential 1
Group 1 (MSSNT)	`017750`	Sequential 2
Group 2 (MSONLY)	`017319`	AFP Tetra
Group 2 (MSONLY)	`010801`	AFP, Open Spina Bifida
Group 2 (SERIN)	`017200`	Serum Integrated 1
Group 2 (SERIN)	`017270`	Serum Integrated 2
Group 3 (AFAFP)	`002428`	AFP, Amniotic Fluid
Group 3 (AFAFP)	`510185`	Chromosome, Amniotic Fluid
Group 3 (AFAFP)	`511580`	Chromosome, AFP/AChE/HbF
Group 3 (AFAFP)	`510305`	AFP/AChE/HbF Amniotic Fluid
Group 4 (SEQUE1)	`451927`	MaterniT21 PLUS Core
Group 4 (SEQUE1)	`451931`	MaterniT21 PLUS Core+ESS
Group 4 (SEQUE1)	`451934`	MaterniT21 PLUS Core+SCA
Group 4 (SEQUE1)	`451937`	MaterniT21 PLUS Core+SCA+ESS
Group 4 (SEQUE1)	`451941`	MaterniT Genome
Group 4 (SEQUE1)	`451951`	MaterniT21 PLUS Core NO Gender

Test cases

Labcorp's Center for Molecular Biology and Pathology (CMBP) publishes 8 test cases that must be passed during certification before the partner is approved for live AFP submissions. They correspond to test cases 25–32 in the certification test plan. See the CMBP Maternal Serum Question Set and Test Cases document.

Microbiology source AOE

Many microbiology tests use a SOURCE AOE to identify where the specimen came from. It is a coded field with a controlled vocabulary, and using free text will fail validation.

Field	Description
`order.specimens.test_codes.aoes` (`SOURCE` AOE)	Micro-specific source value (e.g., `RIGHT EAR`, `WOUND`)

Look values up with the Microbiology source lookup:

GET https://microbiology.services.sandbox.aperture.labcorp.com/: source values for the SOURCE AOE.

The SOURCE value is case-sensitive, and Labcorp expects UPPERCASE.

Histology and pathology body site

Histology and pathology orders identify the body site the specimen came from, optionally with a descriptor/modifier. These are coded fields on the specimen with controlled vocabularies, and using free text will fail validation.

Field	Description
`order.specimens.specimen_characteristics.source_id`	Coded body site/source (e.g., `ABDMN`, `BLOOD`)
`order.specimens.specimen_characteristics.source_text`	Human-readable term (e.g., `abdomen`, `blood`)
`order.specimens.specimen_characteristics.source_site_modifier.identifier`	Optional descriptor/modifier code (e.g., `1C` for "1:00")
`order.specimens.specimen_characteristics.source_site_modifier.text`	Term for the modifier

Look codes up with the Body site lookup:

GET https://body-site.services.sandbox.aperture.labcorp.com/: body site/source codes.
GET https://body-site.services.sandbox.aperture.labcorp.com/descriptors: descriptor/modifier codes.

Conventions:

Codes are case-sensitive and Labcorp expects UPPERCASE for source_id.
The source_text should match the dictionary term exactly. Don't paraphrase.
If you also send a histology observation, the histology specimen must live in its own parent specimen with no other observation objects (see SpecimenCharacteristics in the API reference).

The microbiology and body site lookups are good for refreshing a cached lookup table on a schedule.

Last modified on October 21, 2026

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