← Product Code [CHQ](/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHQ) · K032199

# ESA PLASMA FREE METANEPHRINE ANALYSIS KIT (K032199)

_Esa, Inc. · CHQ · Jan 30, 2004 · Clinical Chemistry · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHQ/K032199

## Device Facts

- **Applicant:** Esa, Inc.
- **Product Code:** [CHQ](/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHQ.md)
- **Decision Date:** Jan 30, 2004
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 862.1165
- **Device Class:** Class 1
- **Review Panel:** Clinical Chemistry

## Indications for Use

The Plasma Free Metanephrine Analysis kit is intended for in vitro diagnostic use in clinical laboratories that hold a CLIA certificate to perform tests of high complexity to measure endogenous free levels of the metanephrines (normetanephrine and metanephrine) in plasma using high performance liquid chromatography with electrochemical detection.

## Device Story

The ESA Plasma Free Metanephrine Analysis Kit is an in vitro diagnostic reagent system used in high-complexity clinical laboratories. It processes human plasma samples to measure endogenous free metanephrine and normetanephrine levels. The workflow involves ion-exchange solid-phase extraction for sample clean-up, followed by evaporation and reconstitution. The prepared samples undergo reversed-phase ion-pair high-performance liquid chromatography (HPLC). Detection is performed via the ESA CoulArray multichannel electrode system, which oxidizes the analytes and an internal standard (HMBA), followed by downstream reduction. Data acquisition, quantitative analysis, and report generation are managed by the ESA CoulArray for Windows Data Station. Clinicians use the resulting quantitative reports to aid in the differential diagnosis of pheochromocytoma. The device provides a standardized method for analyzing plasma-based biomarkers, offering diagnostic utility for patients suspected of having this condition.

## Clinical Evidence

Clinical performance was evaluated using 228 known positive and 651 known negative samples. The assay demonstrated high diagnostic utility in identifying pheochromocytoma. Method comparison against an equivalent HPLC method at the NIH showed strong correlation (r=0.90 for metanephrine; r=0.99 for normetanephrine). Analytical performance included within-run CVs (5.2%–7.5%) and total imprecision CVs (7.8%–10.8%).

## Technological Characteristics

The device utilizes reversed-phase ion-pair HPLC with coulometric electrochemical detection. It employs ion-exchange solid-phase extraction for sample clean-up. The system uses a multichannel electrode array for analyte oxidation/reduction. The assay requires an HPLC system and is intended for professional use in high-complexity clinical laboratories.

## Regulatory Identification

A catecholamines (total) test system is a device intended to determine whether a group of similar compounds (epinephrine, norepinephrine, and dopamine) are present in urine and plasma. Catecholamine determinations are used in the diagnosis and treatment of adrenal medulla and hypertensive disorders, and for catecholamine-secreting tumors (pheochromo-cytoma, neuroblastoma, ganglioneuroma, and retinoblastoma).

## Predicate Devices

- Model 5500 CEAS/Urinary Metanephrine and Norepinephrine

## Submission Summary (Full Text)

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>
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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
DEVICE ONLY TEMPLATE

A. 510(k) Number:
k032199

B. Analyte:
Plasma free metanephrine and free normetanephrine

C. Type of Test:
Quantitative High Performance Liquid Chromatography

D. Applicant:
ESA, Inc.

E. Proprietary and Established Names:
Plasma Free Metanephrine Analysis Kit

F. Regulatory Information:
1. Regulation section:
21 CFR 862.1165
2. Classification:
Class I
3. Product Code:
CHQ
4. Panel:
75 Clinical Chemistry

G. Intended Use:
1. Intended use:
The Plasma Free Metanephrine Analysis kit is intended for in vitro diagnostic use in clinical laboratories that hold a CLIA certificate to perform tests of high complexity to measure endogenous free levels of the metanephrines (normetanephrine and metanephrine) in plasma using high performance liquid chromatography with electrochemical detection.
2. Indication(s) for use:
The analysis of these analytes is used in the differential diagnosis of adult male and female patients with pheochromocytoma.
3. Special condition for use statement(s):
Prescription Use Only
4. Special instrument Requirements:
High performance liquid chromatography

H. Device Description:
The ESA Plasma Free Metanephrine Analysis Kit consists of reagents for the extraction of metanephrines (normetanephrine and metanephrine) sufficient for 100 plasma samples. Sample clean-up is achieved with ion-exchange solid phase extraction. The final extracts are evaporated to dryness, reconstituted and analyzed via reversed phase ion-pair high performance liquid chromatography and electrochemical detection using the ESA CoulArray Detector. The multichannel

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electrode system oxidizes the metanephrines and the internal standard, 4-Hydroxy-3-methoxybenzylamine (HMBA), followed by reduction at a downstream electrode. Total chromatographic run time is approximately 28 minutes per sample.

I. Substantial Equivalence Information:

1. Predicate device name(s): Model 5500 CEAS Urinary Metanephrine and Normetanephrine
2. Predicate K number(s): K931148
3. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Intended Use | Quantitative Measurement of Plasma Free Metanephrines | Quantitative Measurement of Urinary Metanephrines  |
|  Indications for Use | Differential Diagnosis of Pheochromocytoma | Same  |
|  Methodology | High Performance Liquid Chromatography | Same  |
|  Differences  |   |   |
|  Item | Device | Predicate  |
|  Matrix | Plasma | Urine  |

J. Standard/Guidance Document Referenced (if applicable): None referenced

K. Test Principle:

This device is a complete kit for the measurement of plasma metanephrines by high performance liquid chromatography (HPLC) with coulometric electrochemical detection. This method consists of extracting the metanephrines and an internal standard from 1.0 milliliter of venous EDTA plasma with solid phase extraction followed by evaporation, reconstitution and finally injection onto the HPLC system. The solid phase extraction reagents have been optimized to selectively isolate the metanephrines on a cation exchange resin and then elute them at an elevated pH. The extracts are then concentrated by evaporation to provide adequate sensitivity. The HPLC separation uses a very robust reversed phase analytical column and mobile phase combination.

L. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

With-in run imprecision was assessed by measuring three levels each of metanephrine (MN) and normetanephrine (NMN) in a single run with the following results:

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## Metanephrine

|  Mean (pg/mL) | 40.0 | 27.9 | 327.8  |
| --- | --- | --- | --- |
|  SD | 2.9 | 2.0 | 20.5  |
|  CV (%) | 7.3 | 7.0 | 6.2  |
|  N | 11 | 11 | 11  |

## Normetanephrine

|  Mean (pg/mL) | 47.8 | 53.8 | 613.8  |
| --- | --- | --- | --- |
|  SD | 2.7 | 2.8 | 46.3  |
|  CV (%) | 5.6 | 5.2 | 7.5  |
|  N | 11 | 11 | 11  |

Total imprecision was assessed by measuring two levels each of metanephrine (MN) and normetanephrine (NMN). Samples were analyzed in quadruplicate in 20 separate runs over 19 days with the following results:

## Metanephrine

|  Mean (pg/mL) | 78.8 | 252.9  |
| --- | --- | --- |
|  SD | 8.5 | 21.9  |
|  CV (%) | 10.8 | 8.7  |
|  N | 80 | 80  |

## Normetanephrine

|  Mean (pg/mL) | 100.2 | 458.7  |
| --- | --- | --- |
|  SD | 7.8 | 38.6  |
|  CV (%) | 7.8 | 8.4  |
|  N | 80 | 80  |

## b. Linearity/assay reportable range:

Linearity was assessed by spiking in metanephrine and normetanephrine at concentrations of 50, 100, 200, 500, and 1000 pg/mL and assaying the spiked samples. After correcting for endogenous metanephrine and normetanephrine, the following results were obtained:

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## Metanephrine

|  Target | Measured | % Recovery  |
| --- | --- | --- |
|  71 | 81 | 114  |
|  121 | 127 | 105  |
|  221 | 241 | 109  |
|  521 | 560 | 107  |
|  1021 | 1056 | 103  |

## Normetanephrine

|  Target | Measured | % Recovery  |
| --- | --- | --- |
|  69 | 80 | 116  |
|  119 | 119 | 100  |
|  219 | 233 | 106  |
|  519 | 540 | 104  |
|  1019 | 1047 | 103  |

c. Traceability (controls, calibrators, or method):
DL-Normetanephrine hydrochloride and DL-Metanephrine hydrochloride are commercially available standards used to prepare the calibrators and controls for this assay.

d. Detection limit:
The functional sensitivity of these analytes was determined by calculating the coefficient of variation at a designated concentration. The acceptance criteria was a CV of 20% or less. The concentrations chosen were 28 pg/mL for metanephrine and 20 pg/mL for normetanephrine.

e. Analytical specificity:
Analytical specificity and cross-reactivity were assessed qualitatively by directly injecting 62 compounds, including several amine-like compounds, onto the chromatographic column. None of the compounds listed below caused an interfering chromatographic peak.

|   | Mass injected in 100 μL |  | Mass injected in 100 μL |  | Mass injected in 100 μL  |
| --- | --- | --- | --- | --- | --- |
|  2,3 benzo pyrole | 10 ng | Dopamine | 2 ng | Melatonin | 5 ng  |
|  2,5 Dihydroxybenzoic acid | 10 ng | Epinephrine | 2 ng | Methionine | 25 ng  |
|  2-hydroxyphenylacetic acid | 20 ng | Gentisic Acid | 10 ng | Methoxy-hydroxyphenyl glycol | 2 ng  |
|  3-nitro tyrosine | 10 ng | Glutathione | 50 ng | m-tyrosine | 2 ng  |
|  3-hydroxyanthranilic acid | 2 ng | Glutathione (reduced) | 50 ng | n-acetyl serotonin | 2 ng  |

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|  3-hydroxykynurenine | 2 ng | Guanine | 10 ng | Norepinephrine | 2 ng  |
| --- | --- | --- | --- | --- | --- |
|  3-indoxyl phosphate | 15 ng | Guanosine | 20 ng | n-methyl serotonin | 2 ng  |
|  3-o-methyldopa | 2 ng | Homogentisic acid | 2 ng | o-tyrosine | 20 ng  |
|  4-hydroxybenzoic acid | 20 ng | Homovanillic acid | 10 ng | p-tyrosine | 20 ng  |
|  4-hydroxyphenylacetic acid | 20 ng | Hypoxanthine | 10 ng | Salicylic acid | 10 ng  |
|  4-hydroxyphenyllactic acid | 10 ng | Indole-3-acetic acid | 15 ng | Serotonin | 2 ng  |
|  5-hydroxyindoleacetic acid | 25 ng | Indole-3-acetyl-alanine | 15 ng | Tryptamine | 10 ng  |
|  5-hydroxytryptophol | 2 ng | Indole-3-acetyl-glycine | 15 ng | Tryptophan | 20 ng  |
|  5-hydroxytyptophan | 2 ng | Indole-3-acetyl-l-aspartic acid | 15 ng | Tryptophol | 2 ng  |
|  7-methyl guanine | 10 ng | Indole-3-butyric acid | 15 ng | Tyramine | 10 ng  |
|  8- hydroxy guanine | 10 ng | Indole-3-butyryl-8-alanine | 15 ng | Tyrosine | 20 ng  |
|  Acetaminophen | 10 ng | Indole-3-poprionic acid | 2 ng | Uric acid | 1 μg  |
|  Ascorbate | 1 μg | Indole-3-pyruvic acid | 2 ng | Vanillylmandelic acid | 2 ng  |
|  Ascorbic acid | 1 μg | Indoxyl acetate | 15 ng | Xanthine | 20 ng  |
|  Cysteine | 20 ng | Kynurenine | 2 ng | Xanthosine | 100 ng  |
|  Dihydroxphenylacetic acid | 2 ng | L-Dopa | 2 ng |  |   |

f. Assay cut-off: N/A

2. Comparison studies:

a. Method comparison with predicate device:

A method comparison study was performed comparing the device to an equivalent HPLC method at the National Institutes of Health. For metanephrine, 144 samples were compared. The correlation coefficient was 0.90 and the equation of the regression line was:

$$
\mathrm{ESA\ method} = 1.06\ \mathrm{NIH\ method} + 5\ \mathrm{pg/mL}
$$

For normetanephrine, 147 samples were compared. The correlation coefficient was 0.99 and the equation of the regression line was:

$$
\mathrm{ESA\ method} = 1.04\ \mathrm{NIH\ method} + 0.2\ \mathrm{pg/mL}
$$

b. Matrix comparison: N/A

3. Clinical studies:

a. Clinical sensitivity:

Using the sponsor's result interpretation flowchart (see section (c) below), 225 out of 228 known positive samples were correctly identified.

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b. Clinical specificity:

Using the sponsor’s result interpretation flowchart (see section (c) below), 640 out of 651 known negative samples were correctly identified.

c. Other clinical supportive data (when a and b are not applicable):

The following are recommendations by the sponsor regarding the proper use and interpretation of the assay.

As a screening tool, any sample in which the concentration of BOTH normetanephrine and metanephrine are less than the upper reference range limit should be considered normal and the presence of pheochromocytoma is highly unlikely.

Any sample where the concentration of EITHER normetanephrine or metanephrine exceeds their respective upper reference range limit should be considered elevated.

Whenever the normetanephrine or metanephrine concentration exceeds the indeterminate range, the presence of pheochromocytoma is highly probable and should be located via imaging techniques.

There are instances where this assay will yield false positive results. Whenever the results of normetanephrine and/or metanephrine are within but neither result exceeds the indeterminate range, follow-up biochemical testing is suggested according to the flow chart shown below adapted from the National Institutes of Health.

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![img-0.jpeg](img-0.jpeg)

4. Clinical cut-off: N/A
5. Expected values/Reference range: Normetanephrine 18-112 pg/mL Metanephrine 12-61 pg/mL

# M. Conclusion:

Based upon the information provided for the file, I recommend that the ESA Plasma Free Metanephrine Analysis be found substantially equivalent to the predicate device.

---

**Source:** [https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHQ/K032199](https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/CHQ/K032199)

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