LOINC Code 50986-9: Horowitz index (BldV+Inhl gas) [Ratio]

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 Horowitz index. It is commonly used with the system or sample type BldV+Inhl gas.

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
• Order vs observation: Both

What it does not mean

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

Key facts

• Horowitz index in Venous blood
• Horowitz index
• A ratio with numerator = venous oxygen partial pressure (PaO2) in mmHg and denominator = fraction of inspired oxygen (FIO2) with no units. If the patient is breathing room air (20% O2) the fraction would be 0.20. It is reported in mmHg. It is a well established marker for lung function during mechanical ventilation and used in many acuity scores like SAPS II, SAPS III, and SOFA.
• Bld ven; Bld venous; BldV+IhG; Blood - venous; Blood gas ven; Blood ven; Blood venus; Chemistry; Gases; IhG; Inhaled Gas; Inspired; PaO2/FiO2; Point in time; QNT; Quan; Quant; Quantitative; Random; Ratios; Rto; Venous

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

Frequently asked questions