LOINCActive

LOINC Code 28770-6: Maddox double prism test for Heterophoria

28770-6 is a LOINC code used to identify Maddox double prism test for Heterophoria in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Heterophoria. It is commonly used with the system or sample type Eyes.

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Heterophoria. It is commonly used with the system or sample type Eyes.

When is it used?

  • Used in lab systems, EHRs, and clinical data exchange.
  • May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
  • Status: ACTIVE
  • Method: Maddox double prism test

What it does not mean

  • The code identifies the observation or test, not the actual result.

Key facts

  • Maddox double prism test for Heterophoria
  • Heterophoria
  • Used for determination of cyclodeviations. Done by usina a red and white Maddox rod, one placed in front of one eye and the other placed in front of the other eye.
  • Double Maddox rod test; Eye; EYE.HETEROPHORIA; Identity or presence; Nominal; Ophthalmologic; Ophthalmology; Ophtho; Ophthy; Point in time; Random; Vision; Visual

Where you may see this code

You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.

Common synonyms

Maddox double prism test for HeterophoriaMaddox double prism testHeterophoriaEYE.HETEROPHORIAPridPtEyes

Frequently asked questions

Code details

Code28770-6
SystemLOINC
Display nameMaddox double prism test for Heterophoria
DescriptionHeterophoria
Short nameMaddox double prism test
ComponentHeterophoria
PropertyPrid
TimingPt
System (specimen)Eyes
ScaleNom
MethodMaddox double prism test
ClassEYE.HETEROPHORIA
StatusACTIVE

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.00
Last changed2.61

Part names

HeterophoriaPridPtEyesNomMaddox double prism testPresence or IdentityPoint in time (spot)

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.