← Product Code [GKZ](/submissions/HE/subpart-f%E2%80%94automated-and-semi-automated-hematology-devices/GKZ) · K090810

# THERMO SCIENTIFIC CYTO-CAL COUNT TUBES (K090810)

_Microgenics Corp. · GKZ · Sep 18, 2009 · Hematology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/HE/subpart-f%E2%80%94automated-and-semi-automated-hematology-devices/GKZ/K090810

## Device Facts

- **Applicant:** Microgenics Corp.
- **Product Code:** [GKZ](/submissions/HE/subpart-f%E2%80%94automated-and-semi-automated-hematology-devices/GKZ.md)
- **Decision Date:** Sep 18, 2009
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 864.5220
- **Device Class:** Class 2
- **Review Panel:** Hematology

## Indications for Use

Thermo Scientific Cyto-Cal™ Count Tubes are used for determining absolute counts of leucocytes in blood. Thermo Scientific Cyto-Cal™ Count Tubes are used with the immunophenotyping reagents BD TriTEST™, flow cytometers BD FACS Calibur or BD FACS Canto, and software BD CellQuest or DIVA. Thermo Scientific Cyto-Cal™ Count Tubes can be used with the BD FACS™ Loader. This in vitro diagnostic device is intended for clinical use only.

## Device Story

Thermo Scientific Cyto-Cal™ Count Tubes are single-use tubes containing a dried pellet of fluorescent microspheres (5.4 μm) with known concentration. Used in clinical laboratories with flow cytometers (BD FACS Calibur/Canto) and immunophenotyping reagents (BD TriTEST). Whole blood and antibody reagents are added directly to the tube; the pellet dissolves, releasing beads. During flow cytometric analysis, the device enables calculation of absolute cell counts (cells/μL) by comparing the number of positive cellular events to the number of fluorescent bead events. Data analysis is performed via software (e.g., BD MultiSET or BD CellQuest). The bead concentration serves as an internal reference to quantify lymphocyte subsets, aiding clinicians in immunophenotyping assessments.

## Clinical Evidence

Bench testing only. Precision studies (n=21 runs per sample) showed CVs 4.7%-6.9%. Dilution recovery within ±10% of expected values. Method comparison (n=70 samples) against predicate showed correlation coefficient (R) > 0.99 for CD3+ and CD4+ counts. Carryover < 5%. Sample stability confirmed up to 72 hours (refrigerated blood) and 12 hours (labeled/lysed). External evaluation confirmed strong correlation across multiple cell types (CD3, CD4, CD8, CD16, CD19, CD56).

## Technological Characteristics

Single-use tubes containing dried pellet of 5.4 µm fluorescent microspheres. Beads encapsulated with three dyes; emissions equivalent to FITC, PE, Per-CP, PE-Cy5, APC channels. Particle concentration ~50,000/tube. Compatible with flow cytometers (BD FACS Calibur/Canto). Storage 20-25 °C. Shelf-life 16+ months.

## Regulatory Identification

An automated differential cell counter is a device used to identify one or more of the formed elements of the blood. The device may also have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the blood, bone marrow, or other body fluids. These devices may combine an electronic particle counting method, optical method, or a flow cytometric method utilizing monoclonal CD (cluster designation) markers. The device includes accessory CD markers.

## Special Controls

*Classification.* Class II (special controls). The special control for this device is the FDA document entitled “Class II Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells; Final Guidance for Industry and FDA.”

## Predicate Devices

- BD Trucount Tubes ([K965053](/device/K965053.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.
>
> Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/).

{0}

1

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
k090810

B. Purpose for Submission:
Clearance of a new device

C. Measurand:
CD3, CD4, CD8, CD16, CD56, CD19, CD45 Lymphocytes

D. Type of Test:
Quantitative and Semi-quantitative flow cytometric assay

E. Applicant:
Microgenics Corp.

F. Proprietary and Established Names:
Thermo Scientific Cyto-Cal™ Count Tubes

G. Regulatory Information:
1. Regulation section:
864.5220; Differential Cell Counter
2. Classification:
Class II
3. Product code:
GKZ; Automated differential cell counter
4. Panel:
Hematology (81)

H. Intended Use:
1. Intended use(s):
Thermo Scientific Cyto-Cal™ Count Tubes are used for determining absolute counts of leucocytes in blood.
Thermo Scientific Cyto-Cal™ Count Tubes are used with the immunophenotyping reagents BD TriTEST™, flow cytometers BD FACS Calibur or BD FACS Canto, and software BD CellQuest or DIVA.
2. Indication(s) for use:
Same as Intended Use
3. Special conditions for use statement(s):
For Prescription Use Only
4. Special instrument requirements:
Thermo Scientific Cyto-Cal™ Count Tubes are for use with BD TriTEST™ reagent and the BD FACS Calibur or BD FACS Canto analyzers.

I. Device Description:
Thermo Scientific Cyto-Cal™ Count Tubes contain uniform 5.4 um microspheres encapsulated with three proprietary oil soluble dyes. The single tube contains fluorescent beads that have equivalent emissions to multiple channels for FITC, PE, Per-CP, PE-Cy5, APC. Each tube contains a known number of fluorescent particles. Each pouch contains 25 tubes.

{1}

2

J. Substantial Equivalence Information:

1. Predicate device name(s):
BD Trucount Tubes

2. Predicate K number(s):
K965053

3. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Thermo Scientific Cyto-Cal™ Count Tubes | BD Trucount Tubes  |
|  Intended Use | Thermo Scientific Cyto-Cal™ Count Tubes are used for determining absolute counts of leucocytes in blood. Thermo Scientific Cyto-Cal™ Count Tubes are used with the immunophenotyping reagents BD TriTEST™, flow cytometers BD FACS Calibur or BD FACS Canto, and software BD CellQuest or DIVA. Thermo Scientific Cyto-Cal™ Count Tubes can be used with the BD FACS™ Loader. | Used for determining absolute counts leucocytes in blood. BD Trucount Tubes are designed for use with in vitro diagnostic products such as BD TriTest reagents, and a suitably equipped flow cytometer. BD Trucount Tubes can be used with the BD FACS Loader.  |
|  Test Principle | Add the cell typing monoclonal antibody reagent and whole blood directly to the Thermo Scientific Cyto-Cal™ Count Tubes. The dried pellet in the tube dissolves, releasing a known number of fluorescent beads. During analysis, the absolute number (cells/μL) of positive cells in the sample can be determined by comparing cellular events to bead events. If the appropriate software, such as BD MultiSET, is used absolute counts will be determined by the software. If you are manually performing data analysis using software such as BD CellQuest, divide the number of positive cellular events, then multiply by the Thermo Scientific Cyto-Cal™ bead concentration. | Same (only with BD Trucount Tubes)  |
|  Matrix | Dried pellet of fluorescent beads in a single-use tube. | Freeze-dried pellet of fluorescent beads in a single-use tube.  |
|  Instrument | Flow cytometer | Same  |
|  Storage Condition | 2 - 25°C | Same  |
|  Particle Concentration | ~ 50,000/tube | Same  |
|  Lysing reagent | FACS Lyse | Same  |
|  Supplied | Each pouch contains 25 tubes, sufficient for 25 tests. | Same  |

K. Standard/Guidance Document Referenced (if applicable):
Not applicable.

L. Test Principle:
The test principle applies to immunophenotyping of lymphocytes. The cell typing monoclonal antibody reagent and whole blood are directly added to the Thermo

{2}

Scientific Cyto-Cal™ Count Tubes. The dried pellet in the tube dissolves, releasing a known number of fluorescent beads. During analysis, the absolute number (cells/μL) of positive cells in the sample can be determined by comparing cellular events to bead events. If the appropriate software, such as BD MultiSET, is used absolute counts will be determined by the software. If performing manual data analysis using software such as BD CellQuest, divide the number of positive cellular events, then multiply by the Thermo Scientific Cyto-Cal™ bead concentration.

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

### 1. Analytical performance:

#### a. Precision/Reproducibility:

Precision studies were performed to assess absolute count within-run reproducibility for low, normal, and high CD3 and CD3CD4 samples. For each sample, twenty-one (21) aliquots of whole blood were stained with CD3/CD4/CD45 TriTEST reagent using Thermo Scientific Cyto-Cal™ Count Tubes. The range of CVs for CD3 cells, observed for all samples were 4.0% - 6.2%. Acceptance Criteria: Medium and High Cell Concentration Samples - ≤ 5% CV, Low Cell Concentration Samples (Semi-quantitative with-in run) - 7.5% CV. The range of CD3CD4 cells, observed for all samples were 4.3% - 6.9%. Precision data met the acceptance criteria.

Within-run results:

|  Sample | N | Subset | Mean cells/μL | CV%  |
| --- | --- | --- | --- | --- |
|  Low | 21 | CD3+ | 549 | 6.2  |
|   |   |  CD3-CD4+ | 369 | 6.9  |
|  Medium | 21 | CD3+ | 1875 | 3.8  |
|   |   |  CD3-CD4+ | 1220 | 3.9  |
|  High | 21 | CD3+ | 3602 | 4.9  |
|   |   |  CD3-CD4+ | 1996 | 4.7  |

#### b. Linearity/assay reportable range:

To assess linearity and recovery, a dilution recovery study was performed. One fresh whole blood sample was concentrated by removing plasma. This high sample was diluted with serum to 80%, 60% 40%, 20% and 0%. The results are as follows:

Expected results vs. measured values

|  Subset | r | Slope | Intercept  |
| --- | --- | --- | --- |
|  CD3+ | 0.9996 | 0.991 | 17.492  |
|  CD3-CD4+ | 0.9990 | 1.0094 | 12.159  |

Recovery was within 10% of expected value for levels tested.

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

A reagent Shelf-Life Stability study was performed on three lots of Cyto-Cal™ Count Tubes at room temperature (20°-25°C). Bead counts were measured from Day 0 to 16 months and recovery was expected to be within

{3}

$\pm 10\%$  of Day 0 value for up to 16 months. Recovery was greater than  $98\%$  of Day 0 for all three lots for up to 16 months.

d. Detection limit:

Not applicable.

e. Analytical specificity:

An interference study was performed to determine the potential of endogenous and exogenous substances to affect accuracy. The interference was assessed by adding known amounts of interfering substances into whole blood with a  $\mathrm{CD4 + }$  concentration of 398 cells/  $\mu \mathrm{L}$ . Acceptance Criteria:  $\mathrm{CD4 + }$  Count Measured recovers within  $\pm 10\%$  of  $\mathrm{CD4^{+}}$ . No interference was observed for samples adjusted in the pH range of 6.8 - 8.8, in addition to sample conditions listed below:

EDTA: No significant interference from EDTA  $10\mathrm{mg / mL}$

Icterus (jaundice): No significant interference from Bilirubin up to  $20\mathrm{mg / dL}$

Hemoglobin: No significant interference from Hemoglobin up to  $20\mathrm{g / dL}$

Lipemia: No significant interference from Triglycerides up to  $500\mathrm{mg / dL}$

Total Protein: No significant interference from Albumin up to  $12\mathrm{g / dL}$

Package insert lists other substances tested with specific concentrations.

f. Assay cut-off:

Not applicable.

2. Comparison studies:

a. Method comparison with predicate device:

Method comparison studies were performed at one internal site (70 samples) and two external sites (40 samples). The results are as follows:

Internal Site

|  Subset | n | r | Slope | Intercept  |
| --- | --- | --- | --- | --- |
|  CD3+ | 70 | 0.9969 | 0.996 | -0.3  |
|  CD4+ | 70 | 0.9956 | 0.995 | -3.6  |

External Sites combined

|  Subset | n | r | Slope | Intercept  |
| --- | --- | --- | --- | --- |
|  CD3+ | 40 | 0.9769 | 0.967 | -29.4  |
|  CD4+ | 40 | 0.9847 | 1.021 | -29.1  |
|  CD8+ | 40 | 0.9646 | 0.911 | -7.1  |
|  CD16+ CD56+ | 20 | 0.9916 | 1.010 | -7.7  |
|  CD19+ | 20 | 0.9931 | 0.917 | -0.36  |
|  CD4/8 ratio | 40 | 0.9942 | 0.967 | 0.064  |
|  CD45+ | 20 | 0.9812 | 1.016 | -109.6  |

b. Matrix comparison:

Not applicable.

3. Clinical studies:

a. Clinical Sensitivity:

Not applicable.

b. Clinical specificity:

Not applicable.

{4}

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

4. Clinical cut-off:
Not applicable.

5. Expected values/Reference range:
Reference ranges as published by the University of California, San Francisco:
CD3 (T) Cells: 690 – 2540 cells/μL
CD4 (helper – inducer) T Cells: 410 – 1590 cells/μL
CD8 (cytotoxic – suppressor) T Cells: 190 – 1140 cells/μL
CD4/8 (H/S) Ratio: 0.8 – 4.2
CD19 (B) Cells: 90 – 660 cells/μL
CD16, CD56 Natural Killer (NK) Cells: 90 – 590 cells/μL

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 a substantial equivalence decision.

5

---

**Source:** [https://fda.innolitics.com/submissions/HE/subpart-f%E2%80%94automated-and-semi-automated-hematology-devices/GKZ/K090810](https://fda.innolitics.com/submissions/HE/subpart-f%E2%80%94automated-and-semi-automated-hematology-devices/GKZ/K090810)

**Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. If you're preparing [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/), [get in touch](https://innolitics.com/contact).

**Cite:** Innolitics at https://innolitics.com