TearLab is...

An objective and quantitative point-of-care diagnostic test that provides precise and predictive information. 

The TearLab Osmolarity System* is intended to measure the osmolarity of human tears to aid in the diagnosis of dry eye disease in patients suspected of having dry eye disease, in conjunction with other methods of clinical evaluation.

*TearLab is for professional in vitro diagnostic use only.


Test Card
Check Cards Control Solutions

How it works

The TearLab Osmolarity Test Card, in conjunction with the TearLab Osmolarity System, provides a quick and simple method for determining tear osmolarity using nanoliter (nL) volumes of tear fluid collected directly from the eyelid margin. The Test Card is held by the Osmolarity Test Pen, for safe collection.

The TearLab Osmolarity Test utilizes a temperature-corrected impedance measurement to provide an indirect assessment of osmolarity. After applying a lot-specific calibration curve, osmolarity is calculated and displayed as a quantitative numerical value.

To learn how to perform the test, see our Training Videos.

How to perform the test The patient's perspective

Osmolarity: What the numbers reveal

Abnormal Osmolarity is defined by:

Osmolarity is an important indicator of ocular surface health

The MAXIMUM of the eyes


Right Eye
Left Eye

Measurements >300 mOsm/L demonstrate loss of homeostasis. Diagnosis and treatment decisions should be guided by the higher measurement.1

The DIFFERENCE of the eyes

Tear Film Instability

Right Eye
Left Eye

A difference between eyes 8 mOsm/L or greater (intereye difference) indicates instability of the tear film and is a hallmark of dry eye disease.1


Precise and accurate laboratory results at the point-of-care

The Coefficient of Variation of the TearLab Osmolarity System

is lower (better) than most point-of-care lab tests and comparable to the most sophisticated laboratory technologies.

< 1.5%

Lab Test: Osmolarity


Lab Test: Glucose

> 5.0%

Lab Test: Cholesterol

References: 2, 3, 4, 5


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