← Product Code [CHL](/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHL) · K240998

# ABL90 FLEX PLUS System (K240998)

_Radiometer Medicals Aps · CHL · Dec 13, 2024 · Clinical Chemistry · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHL/K240998

## Device Facts

- **Applicant:** Radiometer Medicals Aps
- **Product Code:** [CHL](/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHL.md)
- **Decision Date:** Dec 13, 2024
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 862.1120
- **Device Class:** Class 2
- **Review Panel:** Clinical Chemistry

## Indications for Use

The ABL90 FLEX PLUS System is an in vitro diagnostic, portable, automated analyzer that quantitatively measures pH, blood gas (pO2), Oximetry (sO2, ctHb, FO2Hb, FCOHb, FMetHb, and FHHb), in heparinized arterial and venous whole blood. The ABL90 FLEX PLUS System is intended for use by trained technologists, nurses, physicians and therapists. It is intended for use in a laboratory environment, near patient, or point-of-care setting. These tests are only performed under a physician's order. pH and pO2: pH and pO2 measurements are used in the diagnosis and treatment of life-threatening acid-base disturbances. sO2: Oxygen saturation, more specifically the ratio between the concentration of oxyhemoglobin and oxyhemoglobin plus reduced hemoglobin. ctHb (Total Hemoglobin): Total hemoglobin measurements are used to measure the hemoglobin content of whole blood for the detection of anemia. FO2Hb: Oxyhemoglobin as a fraction of total hemoglobin. FCOHb: Carboxyhemoglobin measurements are used to determine the carboxyhemoglobin content of human blood as an aid in the diagnosis of carbon monoxide poisoning. FMetHb: Methemoglobin as a fraction of total hemoglobin. FHHb: Reduced hemoglobin as a fraction of total hemoglobin..

## Device Story

Portable, automated in vitro diagnostic analyzer; measures pH, pO2, and oximetry parameters in heparinized arterial/venous whole blood. Operates via potentiometry (pH), optical (pO2), and spectrophotometry (oximetry). Used in laboratory or point-of-care settings by trained clinicians. Input: 65 µL whole blood sample via syringe or short probe. Output: Quantitative measurements displayed on touch screen; used by physicians to diagnose acid-base disturbances, anemia, and carbon monoxide poisoning. System includes analyzer, sensor cassettes, and solution packs. Provides rapid diagnostic data to inform clinical decision-making at the point of care.

## Clinical Evidence

Bench testing only. Studies conducted per CLSI guidelines: linearity (EP06, EP39), detection limits (EP17-A2, EP39), precision (EP05-A3), method comparison (EP09c), and interference (EP07, EP37). Precision evaluated using QC ampoules and whole blood across multiple sites. Method comparison against predicate (K160153) showed high correlation (R2 > 0.99) for all parameters. Interference testing identified specific substances (e.g., Intralipid, Methylene Blue) causing measurement errors or clinically significant bias.

## Technological Characteristics

Potentiometry (pH), optical phosphorescence (pO2), and spectrophotometry (oximetry). Portable form factor. Consumables: Sensor cassette and solution pack. Automated fluid transport system. Barcode reader for specimen ID. Connectivity: Standalone analyzer. Calibration: Automated via solution pack and atmospheric air.

## Regulatory Identification

A blood gases (PCO2 , PO2 ) and blood pH test system is a device intended to measure certain gases in blood, serum, plasma or pH of blood, serum, and plasma. Measurements of blood gases (PCO2 , PO2 ) and blood pH are used in the diagnosis and treatment of life-threatening acid-base disturbances.

## Predicate Devices

- ABL90 FLEX PLUS ([K160153](/device/K160153.md))

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
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FDA

U.S. FOOD & DRUG

ADMINISTRATION

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

ASSAY AND INSTRUMENT

## I Background Information:

A 510(k) Number

K240998

B Applicant

Radiometer Medicals ApS

C Proprietary and Established Names

ABL90 FLEX PLUS System

D Regulatory Information

|  Product Code(s) | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  CHL | Class II | 21 CFR 862.1120 - Blood Gases (PCO2, PO2) and Blood pH Test Systems | CH - Clinical Chemistry  |
|  GKR | Class II | 21 CFR 864.5620 – Automated Hemoglobin System | HE - Hematology  |
|  GHS | Class II | 21 CFR 864.7425 – Carboxyhemoglobin Assay | HE - Hematology  |

## II Submission/Device Overview:

A Purpose for Submission:

Modification to a previously cleared device.

Food and Drug Administration

10903 New Hampshire Avenue

Silver Spring, MD 20993-0002

www.fda.gov

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B Measurand:

1. pH (acidity)
2. pO2 (partial pressure of oxygen)
3. sO2 (oxygen saturation)
4. ctHB (total hemoglobin concentration)
5. FO2Hb (Oxyhemoglobin as a fraction of total hemoglobin))
6. FCOHb (Carboxyhemoglobin)
7. FMetHb (Methemoglobin)
8. FHHb (fraction of total hemoglobin)

C Type of Test:

Quantitative - Sensors using Potentiometry for pH measurement; Spectrophotometry for the measurement of sO2, ctHb, FO2Hb, FCOHb, FMetHb, and FHHb; and an Optical System for pO2 measurement.

III Intended Use/Indications for Use:

A Intended Use(s):

See Indications for Use below.

B Indication(s) for Use:

The ABL90 FLEX PLUS System is an in vitro diagnostic, portable, automated analyzer that quantitatively measures pH, blood gas (pO2), Oximetry (sO2, ctHb, FO2Hb, FCOHb, FMetHb, and FHHb), in heparinized arterial and venous whole blood.

The ABL90 FLEX PLUS System is intended for use by trained technologists, nurses, physicians and therapists. It is intended for use in a laboratory environment, near patient, or point-of-care setting.

These tests are only performed under a physician's order.

pH and pO2: pH and pO2 measurements are used in the diagnosis and treatment of life-threatening acid-base disturbances.

sO2: Oxygen saturation, more specifically the ratio between the concentration of oxyhemoglobin and oxyhemoglobin plus reduced hemoglobin.

ctHb (Total Hemoglobin): Total hemoglobin measurements are used to measure the hemoglobin content of whole blood for the detection of anemia.

FO2Hb: Oxyhemoglobin as a fraction of total hemoglobin.

FCOHb: Carboxyhemoglobin measurements are used to determine the carboxyhemoglobin content of human blood as an aid in the diagnosis of carbon monoxide poisoning.

FMetHb: Methemoglobin as a fraction of total hemoglobin.

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FHHb: Reduced hemoglobin as a fraction of total hemoglobin..

## C Special Conditions for Use Statement(s):

Rx - For Prescription Use Only

## D Special Instrument Requirements:

ABL90 FLEX PLUS System

## IV Device/System Characteristics:

### A Device Description:

The ABL90 FLEX PLUS System consists of the ABL90 FLEX PLUS analyzer, sensor cassette (SC) and solution pack (SP) consumables, and related accessories for the analyzer. The ABL90 FLEX PLUS is a portable, automated system intended for in vitro testing of samples of balanced heparinized whole blood for the parameters pH, pO2, pCO2 and co-oximetry parameters (total hemoglobin, oxygen saturation, and the hemoglobin fractions FO2Hb, FCOHb, FMetHb, FHHb and FHbF). The ABL90 FLEX PLUS System has an automated sample inlet mechanism, which can collect the blood through two different measuring modes: the S65 syringe mode and the SP65 short probe mode.

### B Principle of Operation:

There are three different measuring principles employed by the ABL90 FLEX PLUS System: Potentiometry, optical (phosphorescence), and spectrophotometry.

- Potentiometry: The potential of an electrode chain is measured by a voltmeter and related to the concentration of the sample (the Nernst equation). The potentiometric measuring principle is applied in the pH and pCO2 sensors.
- Optical pO2: The optical system for pO2 is based on the ability of O2 to reduce the intensity and time constant of the phosphorescence from a phosphorescent dye that is in contact with the sample. This measuring principle is applied in the pO2 sensor.
- Spectrophotometry: Light passes through a cuvette that contains a hemolyzed blood sample. The absorption spectrum is used to calculate oximetry parameters. This measuring principle is used for ctHb, sO2, FO2Hb, FCOHb, FHHb, and FMetHb.

### C Instrument Description Information:

1. Instrument Name:

ABL90 FLEX PLUS System

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2. Specimen Identification:

The ABL90 FLEX PLUS System has a built-in barcode reader which can scan the barcode on the samples from the patient. The sample identifying barcode can also be entered manually.

3. Specimen Sampling and Handling:

The ABL90 FLEX PLUS System is designed for use with undiluted balanced heparinized human arterial and venous whole blood. Whole blood from arterial or venous specimens can be obtained by needle puncture or via an in-line catheter. Sample volume is 65 µL. The analyzer can aspirate blood samples from different sampling devices, e.g., syringes and test tubes. Regardless of sampling device, the analyzer will automatically aspirate the required volume of the sample and draw it into the closed fluid transport system within the system.

4. Calibration:

The ABL90 FLEX PLUS System calibrates most parameters automatically by use of the calibration solutions in the Solution Pack and by use of atmospheric air for the pO2 sensor.

5. Quality Control:

The analyzer automatically performs quality control checks by measurements on the quality control solutions included in the Solution Pack. The default setting is one quality control measurement every 8 hours. Unscheduled QC measurements can also be performed by the user. Labeling instructs users to follow local, state, and federal guidelines for quality control and calibration verification.

V Substantial Equivalence Information:

A Predicate Device Name(s):

ABL90 FLEX PLUS

B Predicate 510(k) Number(s):

K160153

C Comparison with Predicate(s):

|  Device & Predicate Device(s): | K240998 | K160153  |
| --- | --- | --- |
|  Device Trade Name | ABL90 FLEX PLUS System | ABL90 FLEX PLUS  |
|  General Device Characteristic Similarities |  |   |
|  Indications For Use | The ABL90 FLEX PLUS System is an in | Same  |

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|  Device & Predicate Device(s): | K240998 | K160153  |
| --- | --- | --- |
|   | vitro diagnostic, portable, automated analyzer that quantitatively measures pH, blood gas (pO2), Oximetry (sO2, ctHb, FO2Hb, FCOHb, FMethb, and FHHb), in heparinized arterial and venous whole blood. |   |
|  Intended Use and Environment | The ABL90 FLEX PLUS System is intended for use by trained technologists, nurses, physicians, and therapists in a laboratory environment, near patient, or point-of-care setting. | Same  |
|  Prescription/OTC Use | Prescription Use | Same  |
|  Sample Volume | 65uL | Same  |
|  Consumables | Sensor cassette and Solution pack | Same  |
|  General Device Characteristic Differences |  |   |
|  Test Principles | Potentiometry, optical, and spectrophotometry | Potentiometry, optical, spectrophotometry, and amperometry  |

VI Standards/Guidance Documents Referenced:

Clinical and Laboratory Standards Institute (CLSI) EP05-A3 – Evaluation of Precision of Quantitative Measurement Procedures
CLSI EP09c 3rd Edition – Measurement Procedure Comparison and Bias Estimation Using Patient Samples
CLSI EP17-A2 2nd Edition – Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline
CLSI EP06-2nd Edition – Evaluation of Linearity of Quantitative Measurement Procedures.
CLSI EP07-3rd Edition – Interference Testing in Clinical Chemistry
CLSI EP37 1st Edition – Supplemental Tables for Interference Testing in Clinical Chemistry

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CLSI EP39 1st Edition – A Hierarchical Approach to Selecting Surrogate Samples for the Evaluation of In Vitro Medical Laboratory Tests

# VII Performance Characteristics (if/when applicable):

# A Analytical Performance:

# 1. Precision/Reproducibility:

Point of care precision (aqueous control material):

A multi-day precision study was performed at three point of care (POC) sites using four concentrations of aqueous control solutions. At each site, each level was tested as two replicates per run, two runs per day, for twenty days. At least three POC operators were included at each site. Repeatability, within-laboratory precision, and reproducibility results are reported below:

|  Parameter (units) | QC Level | N | Mean | Repeatability |   | Within Lab Precision |   | Reproducibility  |   |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |   |   |  SD | CV% | SD | CV% | SD | CV%  |
|  pH | L1 | 243* | 7.066 | 0.0034 | 0 | 0 | 0 | 0.0038 | 0.1  |
|   |  L2 | 244 | 7.39 | 0.0018 | 0 | 0 | 0 | 0.0019 | 0  |
|   |  L3 | 244 | 7.582 | 0.0018 | 0 | 0 | 0 | 0.0018 | 0  |
|   |  L4 | 244 | 6.784 | 0.0037 | 0.1 | 0 | 0.1 | 0.0041 | 0.1  |
|  pO2 (mmHg) | L1 | 243* | 154.3 | 1.91 | 1.2 | 2.9 | 1.9 | 3.13 | 2  |
|   |  L2 | 244 | 100.3 | 1.13 | 1.1 | 2 | 2 | 2.01 | 2  |
|   |  L3 | 244 | 56.1 | 0.95 | 1.7 | 1.3 | 2.4 | 1.33 | 2.4  |
|   |  L4 | 244 | 310 | 3 | 1 | 5.5 | 1.8 | 6.95 | 2.2  |
|  sO2 (%) | L1 | 243* | 50 | 0.01 | 0 | 0 | 0 | 0.06 | 0.1  |
|   |  L2 | 244 | 96.9 | 0.03 | 0 | 0.1 | 0.1 | 0.12 | 0.1  |
|   |  L3 | 244 | 70 | 0.01 | 0 | 0 | 0 | 0.03 | 0  |
|   |  L4 | 244 | 5 | 0.01 | 0.2 | 0 | 0.5 | 0.03 | 0.5  |
|  ctHb (g/dL) | L1 | 243* | 8.1 | 0.02 | 0.2 | 0 | 0.4 | 0.04 | 0.6  |
|   |  L2 | 244 | 12.9 | 0.03 | 0.2 | 0 | 0.3 | 0.06 | 0.5  |
|   |  L3 | 244 | 19.3 | 0.03 | 0.2 | 0.1 | 0.3 | 0.09 | 0.5  |
|   |  L4 | 244 | 2.7 | 0.01 | 0.4 | 0 | 0.6 | 0.02 | 0.6  |
|  FO2Hb (%) | L1 | 243* | 44.6 | 0.03 | 0.1 | 0.1 | 0.1 | 0.05 | 0.1  |
|   |  L2 | 244 | 92.2 | 0.04 | 0 | 0.1 | 0.1 | 0.06 | 0.1  |
|   |  L3 | 244 | 49 | 0.02 | 0.1 | 0.1 | 0.1 | 0.05 | 0.1  |
|   |  L4 | 244 | 3.5 | 0.01 | 0.3 | 0 | 0.7 | 0.03 | 0.8  |
|  FCOHb (%) | L1 | 243* | 5.9 | 0.03 | 0.6 | 0.1 | 1 | 0.11 | 1.8  |
|   |  L2 | 244 | 2.8 | 0.03 | 1.1 | 0.1 | 2.9 | 0.13 | 4.7  |
|   |  L3 | 244 | 20 | 0.02 | 0.1 | 0.1 | 0.3 | 0.05 | 0.3  |
|   |  L4 | 244 | 10.1 | 0.02 | 0.2 | 0 | 0.3 | 0.06 | 0.6  |

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|  Parameter (units) | QC Level | N | Mean | Repeatability |   | Within Lab Precision |   | Reproducibility  |   |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |   |   |  SD | CV% | SD | CV% | SD | CV%  |
|  FMetHb (%) | L1 | 243* | 5 | 0.01 | 0.3 | 0 | 0.6 | 0.05 | 0.9  |
|   |  L2 | 244 | 2 | 0.02 | 0.8 | 0 | 2.1 | 0.05 | 2.3  |
|   |  L3 | 244 | 10 | 0.02 | 0.2 | 0 | 0.2 | 0.03 | 0.3  |
|   |  L4 | 244 | 20.1 | 0.04 | 0.2 | 0.1 | 0.3 | 0.09 | 0.4  |
|  FHHb (%) | L1 | 243* | 44.6 | 0.03 | 0.1 | 0.1 | 0.1 | 0.13 | 0.3  |
|   |  L2 | 244 | 3 | 0.02 | 0.7 | 0.1 | 2 | 0.09 | 3.2  |
|   |  L3 | 244 | 21 | 0.01 | 0.1 | 0 | 0.1 | 0.03 | 0.1  |
|   |  L4 | 244 | 66.3 | 0.05 | 0.1 | 0.07 | 0.1 | 0.13 | 0.2  |

*One L1 sample replicate was excluded due to insufficient sample being loaded onto the instrument.

Point of Care precision (Whole Blood):

A multi-day precision study was performed at three sites by at least three POC operators at each site, using balanced heparinized whole blood targeted to levels within the reportable range of each analyte. The whole blood precision was assessed using the duplicate test results collected across multiple point of care sites using both the S65 and SP65 sampling modes. Samples were grouped into subintervals based on their mean values. The results are summarized below.

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|  Parameter (unit) | N | Test interval | Mean | Repeatability  |   |
| --- | --- | --- | --- | --- | --- |
|   |   |   |   |  SD | CV%  |
|  S65 Mode  |   |   |   |   |   |
|  pH | 18 | 6.9 - <7.2 | 7.141 | 0.003 | 0.04  |
|   |  38 | 7.2 - <7.35 | 7.298 | 0.002 | 0.03  |
|   |  130 | 7.35 - <7.45 | 7.405 | 0.003 | 0.04  |
|   |  60 | 7.45 - <7.55 | 7.480 | 0.003 | 0.04  |
|  pO2 (mmHg) | 48 | 30.1 - <60 | 41.904 | 0.252 | 0.60  |
|   |  114 | 60 - <83 | 73.424 | 1.031 | 1.40  |
|   |  42 | 83 - <108 | 90.771 | 1.198 | 1.32  |
|   |  18 | 108 - <150 | 124.50 | 0.850 | 0.68  |
|  ctHb (g/dL) | 24 | 6.750 - 7.950 | 7.533 | 0.082 | 1.08  |
|   |  184 | 8.050 -13.250 | 10.784 | 0.083 | 0.77  |
|   |  34 | 13.550 -17.150 | 14.941 | 0.077 | 0.51  |
|  sO2 (%) | 34 | 3.3 - <80 | 64.221 | 0.890 | 1.39  |
|   |  36 | 80 - <94 | 91.767 | 0.147 | 0.16  |
|   |  158 | 94 - <100 | 96.934 | 0.177 | 0.18  |
|  FO2Hb (%) | 34 | 3.3 - <80 | 63.215 | 0.918 | 1.45  |
|   |  64 | 80 - <94 | 91.677 | 0.146 | 0.16  |
|   |  130 | 94 - <98.5 | 96.083 | 0.165 | 0.17  |
|  FMetHb (%) | 62 | 0.5 - <1.5 | 0.797 | 0.070 | 8.73  |
|   |  4 | 1.5 - <20 | 1.825 | 0.050 | 2.74  |
|   |  12 | 20 - <50 | 40.667 | 0.058 | 0.14  |
|  FCOHb (%) | 162 | 1 - <5 | 1.323 | 0.059 | 4.48  |
|   |  6 | 5 - <35 | 32.733 | 0.058 | 0.18  |
|   |  12 | 35 - <50 | 39.492 | 0.065 | 0.16  |
|  FHHb (%) | 112 | 1.5 - <5 | 2.876 | 0.198 | 6.87  |
|   |  34 | 10 - <40 | 30.297 | 0.860 | 2.84  |
|   |  4 | 40 - <70 | 53.350 | 0.158 | 0.30  |
|  SP65 Mode  |   |   |   |   |   |
|  pH (pH unit) | 18 | 6.9 - <7.2 | 7.135 | 0.003 | 0.05  |
|   |  33 | 7.2 - <7.35 | 7.302 | 0.001 | 0.02  |
|   |  133 | 7.35 - <7.45 | 7.402 | 0.002 | 0.02  |
|   |  60 | 7.45 - <7.55 | 7.482 | 0.001 | 0.01  |
|  pO2 (mmHg) | 49 | 30.1 - <60 | 42.322 | 0.197 | 0.47  |
|   |  96 | 60 - <83 | 73.383 | 0.842 | 1.15  |
|   |  55 | 83 - <108 | 91.136 | 1.343 | 1.47  |
|   |  20 | 108 - <150 | 121.85 | 1.204 | 0.99  |
|  ctHb (g/dL) | 16 | 6.5 - <8 | 7.456 | 0.066 | 0.89  |
|   |  188 | 8 - <13.5 | 10.598 | 0.091 | 0.86  |
|   |  36 | 13.5 - <17.5 | 14.931 | 0.069 | 0.46  |

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|  Parameter (unit) | N | Test interval | Mean | Repeatability  |   |
| --- | --- | --- | --- | --- | --- |
|   |   |   |   |  SD | CV%  |
|  sO2 (%) | 36 | 3.3 - <80 | 62.644 | 0.282 | 0.45  |
|   |  33 | 80 - <94 | 91.858 | 0.203 | 0.22  |
|   |  155 | 94 - <100 | 97.126 | 0.234 | 0.24  |
|  FO2Hb (%) | 36 | 3.3 - <80 | 61.633 | 0.306 | 0.50  |
|   |  59 | 80 - <94 | 91.763 | 0.181 | 0.20  |
|   |  131 | 94 - <98.5 | 96.327 | 0.185 | 0.19  |
|  FMetHb (%) | 62 | 0.5 - <1.5 | 0.777 | 0.070 | 9.04  |
|   |  4 | 1.5 - <20 | 1.825 | 0.050 | 2.74  |
|   |  12 | 20 - <50 | 40.575 | 0.050 | 0.12  |
|  FCOHb (%) | 156 | 1 - <5 | 1.317 | 0.063 | 4.78  |
|   |  6 | 5 - <35 | 32.683 | 0.041 | 0.12  |
|   |  12 | 35 - <50 | 40.367 | 0.058 | 0.14  |
|  FHHb (%) | 109 | 1.5 - <5 | 3.045 | 0.248 | 8.14  |
|   |  30 | 10 - <40 | 31.060 | 0.292 | 0.94  |
|   |  8 | 40 - <70 | 51.963 | 0.137 | 0.26  |

# 2. Linearity:

Linearity testing was conducted in general accordance with CLSI EP06-A2. The linearity of the ABL90 FLEX PLUS System test for pH, pO2, sO2, ctHB, FO2Hb, FCOHb, FMetHb, and FHHb was evaluated by preparing balanced heparinized venous whole blood samples. To achieve target concentrations, samples for pH were adjusted with either HCL or NaOH, samples for ctHB were adjusted for with the addition of plasma and erythrocytes, and samples for sO2, FO2Hb, FHHb, FCOHb, and pO2 were prepared via tonometry. At least 10 replicates were run for each level.

|  Parameter (units) | Reportable Range | Tested Range | Slope | Intercept | R2  |
| --- | --- | --- | --- | --- | --- |
|  pH | 6.818 – 7.797 | 6.605 – 7.997 | 1.047 | -0.342 | 1.000  |
|  pO2 (mmHg) | 30.1 – 488 | 6.110 – 565.600 | 0.994 | -0.543 | 1.000  |
|  sO2 (%) | 3.3 – 100.000 | 2.180 – 100.220 | 1.005 | -0.324 | 1.000  |
|  ctHb (g/dL) | 0.1 – 24.000 | 0.068 – 27.600 | 1.024 | -0.049 | 1.000  |
|  FO2Hb (%) | 3.3 – 98.500 | 2.180 – 98.960 | 1.014 | -0.492 | 1.000  |
|  FCOHb (%) | 1.00 – 92.200 | 0.540 – 95.790 | 1.008 | -0.493 | 1.000  |
|  FMetHb (%) | 0.5 – 91 | 0.490 – 95.610 | 1.033 | 0.068 | 1.000  |
|  FHHb (%) | 1.5 – 98.300 | 0.530 – 98.370 | 0.997 | 0.363 | 1.000  |

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# 3. Analytical Specificity/Interference:

Interference testing was performed according to CLSI EP07-ED3 and CLSI EP37-ED1 and consisted of two parts: paired-difference testing and dose-response experiments.

a. The paired-difference testing was conducted on all potential interferents. Matched samples were tested, one with no interferent and the other with the interferent. If no interference was found, no further testing was performed.
b. The dose-response experiment was only conducted on interferents found to have an effect via the paired-difference testing. This was carried out to determine the concentration at which clinically significant interference occurred.

Freshly drawn heparinized adult venous whole blood was used as starting material for all interference studies. Interference testing was conducted at two levels (i.e., low and high) for pH, pO2, sO2, ctHB, FO2Hb, FCOHb, FMetHb, and FHHb. The following tables list the concentrations of each substance at which no significant interference was found.

Highest concentration tested at which no significant interference is observed

|  Potential interferent for parameter pH | Concentration  |
| --- | --- |
|  Bilirubin, conjugated | 40 mg/dL  |
|  Bilirubin, unconjugated | 40 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Hemolysis | 20%  |
|  Intralipid | 2000 mg/dL  |
|  Propofol | 4.8 mg/dL  |
|  Potassium (-chloride) | 17 mmol/L  |
|  Sodium (-chloride) | 190 mmol/L  |
|  Calcium (-chloride) | 22 mg/dL  |
|  Potential interferent for parameter pO2 | Concentration  |
|  Bilirubin, conjugated | 40 mg/dL  |
|  Bilirubin, unconjugated | 40 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Fluorescein | 40 mg/dL  |
|  Hemolysis | 20%  |
|  Intralipid | 2000 mg/dL  |
|  Propofol | 4.8 mg/dL  |
|  Potential interferent for parameter ctHb | Concentration  |
|  Betacarotene | 0.20 mg/dL  |
|  Bilirubin, conjugated | 40 mg/dL  |
|  Bilirubin, unconjugated | 40 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Cardio green (indocyanine green) | 3 mg/dL  |
|  Evans Blue | 0.50 mg/dL  |
|  Hemolysis | 20%  |
|  Patent blue V (sulphan Blue) | 1 mg/dL  |
|  pH low | 6.8  |
|  pH high | 8.0  |
|  Propofol | 4.8 mg/dL  |

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|  Rifampicin | 6.4 mg/dL  |
| --- | --- |
|  Sodium nitroprusside dihydrate | 87 µg/L  |
|  Triglyceride | 1600 mg/dL  |
|  Potential interferent for parameter sO2 | Concentration  |
|  Betacarotene | 0.20 mg/dL  |
|  Bilirubin, conjugated | 40 mg/dL  |
|  Bilirubin, unconjugated | 40 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Cardio green (indocyanine green) | 3 mg/dL  |
|  Cyanocobalamin | 200 mg/dL  |
|  Evans blue | 0.50 mg/dL  |
|  HbF (fetal hemoglobin) | 80%  |
|  Hemolysis | 20%  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL  |
|  Patent blue V (sulphan Blue) | 1 mg/dL  |
|  pH low | 6.8  |
|  pH high | 8.0  |
|  Potential interferent for parameter FO2Hb | Concentration  |
|  Betacarotene | 0.20 mg/dL  |
|  Bilirubin, conjugated | 40 mg/dL  |
|  Bilirubin, unconjugated | 40 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Cardio green (indocyanine green) | 3 mg/dL  |
|  Evans blue | 0.50 mg/dL  |
|  HbF (fetal hemoglobin) | 80%  |
|  Hemolysis | 20%  |
|  Patent blue V (sulphan Blue) | 1 mg/dL  |
|  pH low | 6.8  |
|  pH high | 8.0  |
|  Potential interferent for parameter FHHb | Concentration  |
|  Betacarotene | 0.20 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Cyanocobalamin | 200 mg/dL  |
|  Evans blue | 0.50 mg/dL  |
|  HbF (fetal hemoglobin) | 80%  |
|  Hemolysis | 20%  |
|  pH low | 6.8  |
|  pH high | 8.0  |
|  Propofol | 4.8 mg/dL  |
|  Rifampicin | 6.4 mg/dL  |
|  Potential interferent for parameter FCOHb | Concentration  |
|  Betacarotene | 0.20 mg/dL  |
|  Bilirubin, conjugated | 40 mg/dL  |
|  Bilirubin, unconjugated | 40 mg/dL  |
|  Biotin | 3510ng/mL  |
|  Cardio green (indocyanine green) | 3 mg/dL  |
|  Evans blue | 0.50 mg/dL  |

{11}

For those substances that on initial screening were found to interfere, dose response testing was conducted to establish the concentration limit below which no significant interference is expected. The results are summarized in the table below:

|  Interferent | Maximum test concentration | Highest concentration without interference | Impact on Test Result  |
| --- | --- | --- | --- |
|  ctHb (test level: 10 g/dL)  |   |   |   |
|  Cyanocobalamin | 200 mg/dL | 25 mg/dL | 1.44 g/dL *  |
|  Fluorescein | 40 mg/dL | 30 mg/dL | -0.72 g/dL *  |
|  HiCN | 30% | 12% | 1.2 g/dL *  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | 25 mg/dL | 2.66 g/dL *  |
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 0.38 mg/dL | -3.94 g/dL *  |
|  SHb | 10% | 5% | -0.86 g/dL **  |
|  ctHb (test level: 20 g/dL)  |   |   |   |
|  Cyanocobalamin | 200 mg/dL | 150 mg/dL | 0.81 g/dL *  |

K240998 - Page 12 of 20

{12}

K240998 - Page 13 of 20
|  Fluorescein | 40 mg/dL | 30 mg/dL | -1.95 g/dL *  |
| --- | --- | --- | --- |
|  HiCN | 30% | 10% | 2.4 g/dL *  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | 50 mg/dL | 2.66 g/dL *  |
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 0.75 mg/dL | -4.15 g/dL *  |
|  SHb | 10% | 2.5% | -1.38 g/dL **  |
|  sO2 (test level: 90%)  |   |   |   |
|  Fluorescein | 40 mg/dL | 20 mg/dL | -5.62%*  |
|  HiCN | 30% | 6.7% | -13%*  |
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 0.75 mg/dL | 3.36%*  |
|  sO2 (test level: 100%)  |   |   |   |
|  Fluorescein | 40 mg/dL | 10 mg/dL | -6.58%*  |
|  HiCN | 30% | 6.3% | -14%*  |
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 1.5 mg/dL | 4.40%*  |
|  FO2Hb (test level: 90%)  |   |   |   |
|  Cyanocobalamin | 200 mg/dL | 150 mg/dL | -7.1%*  |
|  Fluorescein | 40 mg/dL | No interference | 2.4%*  |
|  HiCN | 30% | 3.1% | -37%*  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | 38 mg/dL | -14.7%*  |
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 1.5 mg/dL | 27.0%*  |
|  SHb | 10% | 5% | -7.9%**  |
|  FO2Hb (test level: 100%)  |   |   |   |
|  Cyanocobalamin | 200 mg/dL | 100 mg/dL | -8.5%*  |
|  Fluorescein | 40 mg/dL | 20 mg/dL | 9.16%*  |
|  HiCN | 30% | 3.2% | -40%*  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | 38 mg/dL | -16.7%*  |

{13}

K240998 - Page 14 of 20
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
| --- | --- | --- | --- |
|  Methylene Blue | 6 mg/dL | 1.1 mg/dL | 34.3%*  |
|  SHb | 10% | 5% | -14.6%**  |
|  FHHb (test level: 2.4%)  |   |   |   |
|  Bilirubin (unconj) | 0.684 mmol/L
40 mg/dL | No interference | -0.26%  |
|  Bilirubin (conj) | 0.475 mmol/L
40 mg/dL | No interference | -0.44%  |
|  Cardio green (indocyanine green) | 3 mg/dL | 0.75 mg/dL | -1.16%  |
|  Fluorescein | 40 mg/dL | 10 mg/dL | 7.68%*  |
|  HiCN | 30% | 3.6% | 8.9%*  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | No interference | -0.88%*  |
|  Intralipid | 2000 mg/dL | 800 mg/dL; No measurement result reported above 1600 mg/dL. | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 0.38 mg/dL | -4.44%*  |
|  Patent Blue V (sulphan Blue) | 1 mg/dL | 0.06 mg/dL | -1.78%  |
|  SHb | 10% | 0.5% | 34.5%**  |
|  Sodium nitroprusside dihydrate | 0.87 mg/dL | No interference | -0.08%  |
|  Triglyceride | 1600 mg/dL | 800 mg/dL | 1.42%  |
|  FHHb (test level: 10%)  |   |   |   |
|  Bilirubin (unconj) | 0.684 mmol/L
40 mg/dL | 0.17 mmol/L
10 mg/dL | -0.82%*  |
|  Bilirubin (conj) | 0.475 mmol/L
40 mg/dL | 0.06 mmol/L
5 mg/dL | -0.88%*  |
|  Cardio green (indocyanine green) | 3 mg/dL | 0.75 mg/dL | -2.0%  |
|  Fluorescein | 40 mg/dL | 5 mg/dL | 7.34%*  |
|  HiCN | 30% | 4.5% | 6.1%*  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | 150 mg/dL | -1.26%*  |
|  Intralipid | 2000 mg/dL | 1200 mg/dL; No measurement result reported above 1600 mg/dL. | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 0.38 mg/dL | -1.58%*  |
|  Patent Blue V (sulphan Blue) | 1 mg/dL | 0.006 mg/dL | -0.98%  |

{14}

|  SHb | 10% | 2.5% | 17.2%**  |
| --- | --- | --- | --- |
|  Sodium nitroprusside dihydrate | 0.87 mg/dL | 0.22 mg/dL | -0.52%  |
|  Triglyceride | 1600 mg/dL | 1200 mg/dL | 1.20%  |
|  FCOHb (test level: 1%)  |   |   |   |
|  Cyanocobalamin | 200 mg/dL | 50 mg/dL | 1.7%*  |
|  Fluorescein | 40 mg/dL | 2.5 mg/dL | -10.64%*  |
|  HiCN | 30% | 3.4% | 6.3%*  |
|  Intralipid | 2000 mg/dL | 1600 mg/dL; No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | No interference | 0.64%*  |
|  SHb | 10% | 1.25% | 1.08%**  |
|  FCOHb (test level: 10%)  |   |   |   |
|  Cyanocobalamin | 200 mg/dL | 100 mg/dL | 1.1%*  |
|  Fluorescein | 40 mg/dL | 3.75 mg/dL | -10.84%*  |
|  HiCN | 30% | 9.6% | 2.9%*  |
|  Intralipid | 2000 mg/dL | 1600 mg/d;L No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 1.5 mg/dL | 1.88%*  |
|  SHb | 10% | 2.5% | 1.58%**  |
|  FMetHb (test level: 1.0%)  |   |   |   |
|  Cardio green (indocyanine green) | 3 mg/dL | 1.5 mg/dL | -1.48%  |
|  Cyanocobalamin | 200 mg/dL | 12.5 mg/dL | 5.44%*  |
|  Fluorescein | 40 mg/dL | 30 mg/dL | -9.88%*  |
|  HiCN | 30% | 1.1% | 24%*  |
|  Hydroxo-cobalamine hydrochloride | 200 mg/dL | 8 mg/dL | 13.1%*  |
|  Intralipid | 2000 mg/dL | 1200 mg/dL No measurement result reported above 1600 mg/dL | Error message “Turbidity too high.”  |
|  Methylene Blue | 6 mg/dL | 0.08 mg/dL | -33%*  |
|  pH low | 6.8 | No interference | 0.96%  |
|  pH high | 8.0 | No interference | -0.76%  |
|  SHb | 10% | No interference | -0.7%**  |
|  Triglyceride | 1600 mg/dL | 1200 mg/dL | 0.96%  |

*At the concentrations that might cause interference, the instrument reports an error message when these substances are detected with error message: “OXI spectrum mismatch”.

K240998 - Page 15 of 20

{15}

** At the concentrations that might cause interference, the result is marked with error message "Warning, SHb detected."

The sponsor also included the following limitation in their labeling: "The specificity of absorbance measurements for tHb, sO2, O2Hb, HHb, COHb, and MetHb is determined by the optical system – spectrophotometer and algorithm. Substances that change the color of the blood may absorb light at the same wavelengths as the analyte and give interference on the optical oximetry measurement. The ABL90 FLEX PLUS System is able to identify some of these interferents at therapeutic levels in samples, including Fluorescein, HiCN, Methylene Blue, and Cyanocobalamin and will indicate the "OXI spectrum mismatch" error. However, Patent Blue V (sulphan Blue), Sodium nitroprusside dihydrate, Cardio green (indocyanine green), and Hydroxo-cobalamine hydrochloride at therapeutic levels or levels expected in patients can cause interference in samples not detected and flagged by the ABL90 FLEX PLUS System. See interferences section for more information."

# 4. Assay Reportable Range:

See section A.2 Linearity.

# 5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):

pH: Traceable to IUPAC pH scale via commercially available certified reference material. pO2: Traceable to the International System of Units (SI) via commercially available certified specialty medical gas standards.

ctHb: Traceable to SI using HiCN method (CLSI H15 - Reference and Selected Procedures for the Quantitative Determination of Hemoglobin in Blood, 3rd Edition.).

# 6. Detection Limit:

Detection capability testing was conducted in general accordance with CLSI EP17-A2. To achieve target concentrations, heparinized venous whole blood samples for pH were adjusted with either HCL or NaOH, samples for ctHB were adjusted for with the addition of aqueous buffer solution with or without erythrocytes, samples for FMetHb were adjusted using isotonic saltwater, and samples for sO2, FO2Hb, FHHb, FCOHb, and pO2 were prepared via tonometry. Testing was performed on the ABL90 FLEX PLUS System using 3 reagent lots, 9 instruments, over the course of 9 days, using 4 independent samples, with at least 5 replicates/sample, and 60 replicates/reagent lot.

|  Parameter (units) | Reportable Range | LoQ results  |
| --- | --- | --- |
|  pH | 6.818 – 7.797 | 6.754  |
|  pO2 (mmHg) | 30.1 – 488 | 7.7  |
|  sO2 (%) | 3.3 – 100.0 | 1.4  |
|  ctHb (g/dL) | 0.1 – 24.0 | 0.09  |
|  FO2Hb (%) | 3.3 – 98.5 | 1.4  |

K240998 - Page 16 of 20

{16}

|  Parameter (units) | Reportable Range | LoQ results  |
| --- | --- | --- |
|  FCOHb (%) | 1.00 – 92.2 | 0.7  |
|  FMetHb (%) | 0.5 – 91 | 0.3  |
|  FHHb (%) | 1.5 – 98.3 | 1.4  |

7. Assay Cut-Off:
Not applicable.

8. Accuracy (Instrument):
See section B.1 Method Comparison.

9. Carry-Over:
Not applicable.

B Comparison Studies:

1. Method Comparison with Predicate Device:
Method comparison for arterial and venous whole blood specimens on the ABL90 FLEX PLUS System was done in general accordance with CLSI EP09c-ED3. Heparinized arterial and venous whole blood specimens (maximum of 10% contrived) collected across 4 POC sites, with at least two POC users per site were compared to whole blood specimens tested on a comparative method. Specifically, each sample was measured once on the candidate device in one mode (i.e. S65 or SP65) and once on the predicate device in the same mode. Evaluations were performed per each combination of parameter, blood type, and sampling mode by linear regression. The regression analysis for these samples are summarized below.

K240998 - Page 17 of 20

{17}

Method Comparison Results for S65 mode

|  Parameter | n | Intercept | Slope | R2 | Medical decision point | Bias at MD  |
| --- | --- | --- | --- | --- | --- | --- |
|  pO2 (mmHg) | 401 | 0.111 | 0.999 | 0.999 | 83.000 | 0.002  |
|   |   |   |   |   |  108.00 | -0.031  |
|  pH (pH scale) | 442 | 0.018 | 0.997 | 0.998 | 7.350 | -0.003  |
|   |   |   |   |   |  7.450 | -0.003  |
|  sO2 (%) | 422 | -0.441 | 1.006 | 0.999 | 94.000 | 0.134  |
|   |   |   |   |   |  80.000 | 0.048  |
|  tHb (g/dL) | 427 | 0.015 | 1.006 | 0.994 | 8.400 | 0.068  |
|   |   |   |   |   |  17.500 | 0.126  |
|  O2Hb (%) | 411 | -0.492 | 1.007 | 0.999 | 94.000 | 0.160  |
|   |   |   |   |   |  80.000 | 0.063  |
|  HHb (%) | 338 | -0.023 | 1.003 | 0.999 | 10.000 | 0.005  |
|   |   |   |   |   |  5.000 | -0.009  |
|  COHb (%) | 322 | -0.332 | 1.002 | 0.999 | 10.000 | -0.307  |
|   |   |   |   |   |  25.000 | -0.271  |
|  MetHb (%) | 49 | -0.229 | 1.008 | 1.000 | 1.500 | -0.217  |
|   |   |   |   |   |  20.000 | -0.075  |

Method Comparison Results for SP65 mode

|  Parameter | n | Intercept | Slope | R2 | Medical decision point | Bias at MD  |
| --- | --- | --- | --- | --- | --- | --- |
|  pO2 (mmHg) | 396 | -0.166 | 1.003 | 0.999 | 83.000 | 0.042  |
|   |   |   |   |   |  108.00 | 0.105  |
|  pH (pH scale) | 427 | 0.023 | 0.996 | 0.999 | 7.350 | -0.003  |
|   |   |   |   |   |  7.450 | -0.003  |
|  sO2 (%) | 404 | -0.395 | 1.006 | 0.999 | 94.000 | 0.212  |
|   |   |   |   |   |  80.000 | 0.122  |
|  tHb (g/dL) | 412 | 0.069 | 1.001 | 0.996 | 8.400 | 0.076  |
|   |   |   |   |   |  17.500 | 0.084  |
|  O2Hb (%) | 393 | -0.381 | 1.005 | 0.999 | 94.000 | 0.123  |
|   |   |   |   |   |  80.000 | 0.048  |
|  HHb (%) | 318 | -0.117 | 1.003 | 0.999 | 10.000 | -0.089  |
|   |   |   |   |   |  5.000 | -0.103  |
|  COHb (%) | 305 | -0.394 | 0.993 | 0.999 | 10.000 | -0.462  |
|   |   |   |   |   |  25.000 | -0.564  |
|  MetHb (%) | 42 | -0.290 | 1.012 | 1.000 | 1.500 | -0.272  |
|   |   |   |   |   |  20.000 | -0.055  |

K240998 - Page 18 of 20

{18}

2. Matrix Comparison:

Not applicable since the only sample types recommended for the candidate device are balanced heparinized venous and arterial whole blood.

C Clinical Studies:

1. Clinical Sensitivity:

Not applicable.

2. Clinical Specificity:

Not applicable.

3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):

Not applicable.

D Clinical Cut-Off:

Not applicable.

E Expected Values/Reference Range:

Below are general reference ranges, cited from literature, for a normal, healthy population.

|  Parameter | Reference Range  |
| --- | --- |
|  pH | 7.35 – 7.45^{1}  |
|  pO2 (mmHg) | 83 – 1081^{1}  |
|  sO2 (%) | 94-100^{2}  |
|  ctHb (g/dL) | 13.5 – 17.53 (male) / 12.0 – 16.03 (female)^{2}  |
|  FO2Hb (%) | 94 – 98^{2}  |
|  FCOHb (%) | 0-10^{2}  |
|  FMetHb (%) | 0.0 – 1.5^{1}  |
|  FHHb (%) | 0 – 5^{2}  |

1 Tietz NW, Logan NM. Reference ranges, In: Fundamentals of clinical chemistry. 3rd ed. Philadelphia: WB Saunders Company 1987: 944-75.
2 Burtis CA, Ashwood ER, Bruns DE. Tietz textbook of clinical chemistry and molecular diagnostics. 5th ed. St. Louis: Saunders Elsevier, 2012.

K240998 - Page 19 of 20

{19}

VIII Proposed Labeling:

The labeling supports the finding of substantial equivalence for this device.

IX Conclusion:

The submitted information in this premarket notification is complete and does support a substantial equivalence decision.

K240998 - Page 20 of 20

---

**Source:** [https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHL/K240998](https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHL/K240998)

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