TearLab -Osmolarity System
TearLab® Osmolarity System - An Essential Diagnostic for Dry Eye Disease. 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.
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.
Tear osmolarity is informative when the results are abnormal or normal.
Abnormal Osmolarity is defined by:
- An elevated reading, >300 mOsm/L, indicating loss of homeostasis.
- OR, When the inter-eye difference is >8 mOsm/L, indicating instability of the tear film.
In a prospective observational study of 50 symptomatic patients with normal tear osmolarity, the most frequent diagnoses included:†
PRECISE: More precise than other universally accepted point-of-care tests such as cholesterol and glucose.
- TearLab has a positive predictive value of 89%.
- Positive predictive value is the probability that subjects with a positive test truly have the disease.