# K191496: TDS Standard Solution

- Pathway: 510(k) (Traditional)
- Applicant: Mesa Laboratories, Inc.
- Decided: Aug 5, 2019 after 61 days
- Product code: FKH (Solution-Test Standard-Conductivity, Dialysis)
- Device class: 2
- Regulation: 21 CFR 876.5820
- Recalls of this device: none
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 2 generations back to K851362 (1985). 2 ancestors in all.
No later device cites it as a predicate yet.
0 of 3 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- K033330: Conductivity/TDS Calibrator Solution, Mesa Laboratories, Inc. (2004) Summary page 4.

## Indications for use
This TDS Standard Solution is indicated for verifying the accuracy (calibration) of TDS (Total Dissolved Solids) meters. This standard solution should be used immediately before conductivity meters are used to determine the conductivity of water obtained from water purification systems used in hemodialysis. This solution is prepared from a mixture of salts comprised of 40% Sodium Bicarbonate, 40% Sodium Sulfate, and 20% Sodium Chloride which is intended to mimic natural water systems. These solutions are used remotely from the water purification equipment, and do not come into contact with the patient.

Source page: https://510kreport.com/device/K191496
Methodology: https://510kreport.com/methodology