PLATELETWORKS ARACHIDONIC ACID, MODEL PW-ACA

K061991 · Helena Laboratories · GHR · Feb 23, 2007 · Hematology

Device Facts

• Record ID: K061991
• Device Name: PLATELETWORKS ARACHIDONIC ACID, MODEL PW-ACA
• Applicant: Helena Laboratories
• Product Code: GHR · Hematology
• Decision Date: Feb 23, 2007
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 864.5700
• Device Class: Class 2

Indications for Use

Plateletworks Arachidonic Acid (PW-ACA) is an in vitro diagnostic screening test on whole blood for the qualitative determination of platelet inhibition by aspirin which inhibit arachidonic acid induced platelet aggregation. The change in platelet count due to activation and aqqreqation of functional platelets is measured using an electronic impedance-base cell counter.

Device Story

Plateletworks Arachidonic Acid (PW-ACA) is an in vitro diagnostic test for assessing aspirin-induced platelet inhibition. The device utilizes whole blood samples; it measures the change in platelet count resulting from arachidonic acid-induced activation and aggregation. The principle of operation relies on an electronic impedance-based cell counter to quantify functional platelet aggregation. The test is performed in a clinical laboratory setting by trained personnel. Results are provided to healthcare providers to assist in evaluating the efficacy of aspirin therapy in inhibiting platelet function. By identifying patients with inhibited platelet aggregation, the device aids in clinical decision-making regarding antiplatelet therapy.

Clinical Evidence

No clinical data provided. Substantial equivalence is based on bench testing demonstrating the performance of the electronic impedance-based cell counting method for measuring platelet aggregation induced by arachidonic acid.

Technological Characteristics

In vitro diagnostic kit; includes baseline tubes (K3 EDTA) and arachidonic acid (porcine liver). Measurement principle: electronic impedance-based cell counting. Qualitative screening assay. Requires external electronic impedance-based cell counter for analysis.

Indications for Use

Indicated for qualitative screening of platelet inhibition by aspirin in adult patients (>18 years) via arachidonic acid-induced aggregation in whole blood.

Regulatory Classification

Identification

An automated platelet aggregation system is a device used to determine changes in platelet shape and platelet aggregation following the addition of an aggregating reagent to a platelet-rich plasma.

Predicate Devices

• Plateletworks (K061991)

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY TEMPLATE

A. 510(k) Number:
K061991

B. Purpose for Submission:
New Device

C. Measurand:
Platelets

D. Type of Test:
Aggregation, qualitative

E. Applicant:
Helena Laboratories

F. Proprietary and Established Names:
Plateletworks Arachidonic Acid Kit

G. Regulatory Information:
1. Regulation section:
21 CFR 864.5700, Automated Platelet Aggregation System
2. Classification:
Class II
3. Product code:
GHR, Reagent, Platelet Aggregation
4. Panel:
81 (Hematology)

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H. Intended Use:

1. Intended use(s):

Plateletworks Arachidonic Acid (PW-ACA) is an in vitro diagnostic screening test on whole blood for the qualitative determination of platelet inhibition by aspirin which inhibit arachidonic acid induced platelet aggregation. The change in platelet count due to activation and aggregation of functional platelets is measured using an electronic impedance-based cell counter.

2. Indication(s) for use:

Plateletworks Arachidonic Acid (PW-ACA) is an in vitro diagnostic screening test on whole blood for the qualitative determination of platelet inhibition by aspirin which inhibit arachidonic acid induced platelet aggregation. The change in platelet count due to activation and aggregation of functional platelets is measured using an electronic impedance-based cell counter.

3. Special conditions for use statement(s):

Not applicable.

4. Special instrument requirements:

Not applicable.

I. Device Description:

The Plateletworks Arachidonic Acid Kit contains 25 baseline tubes (contain K3 EDTA) and 25 ACA tubes (arachidonic acid isolated from porcine liver) and a % Aggregation/Inhibition chart.

J. Substantial Equivalence Information:

1. Predicate device name(s):

Arachidonic Acid

2. Predicate 510(k) number(s):

K912774

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3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| | Plateletworks Arachidonic Acid | Arachidonic Acid |
| Intended Use | For the qualitative determination of platelet inhibition by aspirin which inhibit arachidonic acid induced platelet aggregation. The change in platelet count due to activation and aggregation of functional platelets is measured using an electronic impedance-based cell counter. | For use in platelet aggregometry studies. |
| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| | Plateletworks Arachidonic Acid | Arachidonic Acid |
| Function | Measures aggregation of platelets in response to an agonist using impedance hematology counter to measure aggregation | Measures aggregation of platelets in response to an agonist using light transmission to measure aggregation. |
| Sample | Citrated whole blood | Citrated platelet rich plasma |
| Measurement | Screening (qualitative) | Direct measurement (quantitative) |

K. Standard/Guidance Document Referenced (if applicable):

EP5A Evaluation of Precision Performance of Clinical Chemistry Device Approved Guideline, NCCLS

L. Test Principle:

Traditional platelet aggregometry, the reference method for testing platelet function, is based on the addition of the platelet agonist to a blood sample (usually platelet rich plasma). Platelet aggregation may be assessed using various agonists such as ADP, collagen, and others. Arachidonic acid is a fatty acid which is liberated from the human platelets on activation and is converted by the enzyme cyclooxygenase into a potent inducer of platelet aggregation. Ingestion of aspirin or other similar drugs inhibits cyclooxygenase-1 (COX-1) thus inhibiting platelet aggregation.

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The Plateletworks methodology is an adaptation of platelet aggregometry that is extremely simple, inexpensive, and quick to perform. This two step method involves using a cell counter to measure total platelet count in a whole blood sample and to re-determine the platelet count on a second sample that has been exposed to a known platelet agonist. The agonist will stimulate those platelets which are functional to aggregate into clumps and they will not be counted as platelet in the second sample. The difference ion the platelet count between samples one and two provides a direct measurement of platelets aggregation and is reported as percent aggregation.

## M. Performance Characteristics (if/when applicable):

### 1. Analytical performance:

a. Precision/Reproducibility:

Precision was determined by testing an aspirin donor (in duplicate) for 10 days, 1 run per day. Results are as follows:

Within run CV = 23.0% Total SD = 6.7

Lot to lot reproducibility was evaluated using normal and abnormal donors on six product lots. Results were acceptable.

b. Linearity/assay reportable range:

Not applicable.

c. Traceability, Stability, Expected values (controls, calibrators, or methods):

Data to support stability was provided for six lots. Normal donors were used for testing and 60% or greater aggregation was detected. A nine month shelf-life was assigned.

d. Detection limit:

Not applicable.

e. Analytical specificity:

Not applicable.

f. Assay cut-off:

Not applicable.

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2. Comparison studies:

Not applicable.

a. Method comparison with predicate device:

Not applicable.

b. Matrix comparison:

Not applicable.

3. Clinical studies:

Correlation studies were performed by testing male and female adults, greater than 18 years of age, at four clinical sites with two laboratory methods: Reference – LTA (Light Transmission Aggregometry) and Test – PW-ACA. The subjects included normal, healthy individuals, in addition to, patients and individuals that were taking aspirin (325 mg, 162 mg, and 81 mg).

Comparison of two Laboratory Methods

| | | 95% confidence limits |
| --- | --- | --- |
| Agreement | 87.54 % | (83.53 to 90.87%) |
| Positive Agreement | 93.20 % | (86.50-97.22%) |
| Negative Agreement | 85.04% | (79.82-89.35%) |

a. Clinical Sensitivity:

Plateletworks ACA with aspirin and non aspirin donors: 0.970

b. Clinical specificity:

Plateletworks ACA with aspirin and non aspirin donors: 0.875

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

4. Clinical cut-off:

Not applicable.

5. Expected values/Reference range:

Normal donors (173), who had not taken aspirin or other medications (which inhibit platelet aggregation), were tested and a normal range was determined with a cut off value of $\geq 60\%$. The same donors were tested with Light Transmission Aggregometry (LTA). The recommended range of $60 - 100\%$ compensates for the qualitative/screening nature of the test system.

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N. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:

The submitted information in this premarket notification is complete and supports substantial equivalence decision.

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