The Chempaq XBC Analyzer is an in vitro diagnostic method intended for the quantitative determination of the concentration of white blood cells ("WBC"); granulocytes ("GRN"); lymphocytes ("LYM"); monocytes ("MON"); and total hemoglobin ("Hb") in whole blood samples (finger stick or venous sample). The Compaq XBC Analyzer is indicated for use in: clinical laboratories, and for point-of-care hematology determinations in doctors' offices or by healthcare professionals in hospital settings to identify and classify one or more of the formed elements of blood.
Device Story
The Chempaq XBC Analyzer is a point-of-care hematology system consisting of a stationary 'Cradle' reader and a single-use 'PAQ' cartridge. The user applies a whole-blood sample to the PAQ cartridge and inserts it into the Cradle; electrical and pneumatic connections between the cartridge and reader facilitate automated sample manipulation and analysis. The device performs all required reagent handling internally within 3 minutes. The system provides quantitative results for WBC, granulocytes, lymphocytes, monocytes, and hemoglobin. It is intended for use by healthcare professionals in clinical laboratories, doctors' offices, and hospital settings to identify and classify blood elements. The output assists clinicians in hematological assessment and decision-making.
Clinical Evidence
Performance validation included laboratory bench testing and point-of-use clinical testing in physician office laboratories and point-of-care settings. Parameters evaluated included precision, accuracy, venous vs. capillary sample comparison, linearity, interferences, pre-analytical errors, stability, and batch variability. Testing followed NCCLS and ICSH protocols. Results confirmed the device functioned as intended.
Technological Characteristics
System comprises a single-use PAQ cartridge and a stationary Cradle reader. Employs electrical and pneumatic connections for automated sample manipulation and reagent handling. Standalone point-of-care form factor. No user reagent manipulation required. Analysis time is 3 minutes.
Indications for Use
Indicated for quantitative determination of WBC, granulocytes, lymphocytes, monocytes, and hemoglobin in whole-blood (finger stick or venous) samples. Used in clinical laboratories, doctors' offices, and hospital settings by healthcare professionals.
Regulatory Classification
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.”
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY INSTRUMENT ONLY TEMPLATE
A. 510(k) Number:
K050758
B. Purpose for Submission:
New Device
C. Manufacturer and Instrument Name:
Chempaq A/S, Chempaq XBC Analyzer
D. Type of Test or Tests Performed:
Quantitative, White Blood Cells (WBC), Granulocytes (GRN), Lymphocytes (LYM), Monocytes (MON), Total Hemoglobin (Hb)
E. System Descriptions:
1. Device Description:
The Chempaq XBC Analyzer is an automated differential cell counter. The device consists of the following components and accessories: (1) a single use cartridge, called the Particle Analyzer and Qualifier (PAQ); and (2) a stationary Reader with a docking station, called a Cradle. The PAQ is connected to the Cradle by a simple push fit. The PAQ includes all required reagents and will, when connected to the Cradle, perform all simple manipulations required for the analysis. The sample manipulation is facilitated by electrical and pneumatic connections between the PAQ and the Cradle.
2. Principles of Operation:
The Chempaq XBC Analyzer counts and sizes blood cells by impedance cell sizing, also known as the Coulter Sizing or Coulter Counting Principle. This concept is broadly accepted as being used in most hematology analyzers and particle counting equipment. The method is based on measurable changes in the electrical impedance produced by comparatively non-conductive particles in an electrolyte.
3. Modes of Operation:
Random access, Point of Care
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4. Specimen Identification:
Not Available, Manual numbering
5. Specimen Sampling and Handling:
The Chempaq XBC Analyzer analyzes a single drop (20 µL) of blood usually taken from the fingertip or a well mixed sample of venous blood already taken from the patient. Capillary blood sample from the fingertip is obtained by standard techniques and any lancing system that provides sufficient blood.
Venous samples should be collected in containers carrying salts of EDTA as anticoagulant in a concentration of 3.7-5.4 µmol/mL of blood. The blood sample should be at room temperature and well mixed. A pipette capable of safely delivering a single drop of blood should be used to apply to the blood inlet of the PAQ.
Heparin cannot be used as an anticoagulant.
6. Calibration:
The Chempaq XBC Analyzer is factory calibrated when manufactured. The method of calibration is traceable to Clin. Lab. Haemat., 16(2), 131-138 (1994) for WBC and NCCLS standard H15-A3 for Hgb.
7. Quality Control:
External controls are indicated to be necessary to meet conformance with local, state and federal regulations. An available commercial control is suggested.
8. Software:
The Chempaq XBC Analyzer software is developed only for operating the instrument and considered to be of moderate level of concern. Algorithms for the blood cell counts and hemoglobin measurement are included in the software and validated accordingly.
FDA has reviewed applicant's Hazard Analysis and Software Development processes for this line of product types
Yes ☐ X or No ☐
F. Regulatory Information:
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1. Regulation section:
21 CFR 864.5220 Automated Differential Cell Counter
2. Classification:
Class II
3. Product code:
GKZ, Counter, Differential Cell
4. Panel:
(81) Hematology
G. Intended Use:
1. Indication(s) for Use:
The Chempaq XBC Analyzer is an in vitro diagnostic method intended for the quantitative determination of the concentration of white blood cells ("WBC"); granulocytes ("GRN"); lymphocytes ("LYM"); monocytes ("MON"); and total hemoglobin ("Hb") in whole blood samples (finger stick or venous sample).
The Compaq XBC Analyzer is indicated for use in: clinical laboratories, and for point-of-care hematology determinations in doctors' offices or by healthcare professionals in hospital settings to identify and classify one or more of the formed elements of blood.
2. Special Conditions for Use Statement(s):
Not applicable.
H. Substantial Equivalence Information:
1. Predicate Device Name(s) and 510(k) numbers:
Coulter® A™ Diff Analyzer, K973634
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# 2. Comparison with Predicate Device:
| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| | Chempaq XBC Analyzer | Coulter® A^CT™ Diff Analyzer |
| Intended Use | A hematology analyzer used for the quantitative determination of the concentration of white blood cells (“WBC”); granulocytes (“GRN”); lymphocytes (“LYM”); monocytes (“MON”); and total hemoglobin (“Hb”) in whole blood samples (finger stick or venous sample). | A quantitative, automated hematology analyzer used for determination of the following CBC parameters: WBC, red blood cells (“RBC”), hemoglobin (“Hb”), hematocrit (“Hct”), mean corpuscular hemoglobin (“MCH”), mean corpuscular volume (“MCV”), mean corpuscular hemoglobin concentration (“MCHC), platelet count (“Plt”), LYM %/#, MON %/#, GRN %/#, RDW, and MPV. |
| User Population | Healthcare professionals | For use in clinical laboratories |
| Patient Samples | Whole blood from finger stick or venous samples. | Same |
| Safety Features | Built-in calibration and flagging system | Same |
| Reagents | Reagent system includes lytic reagent. | Reagent system includes isotonic diluent, lytic reagent, and cleaning agent. |
| Technological Characteristics | (1) Uses the Coulter principle for enumeration and sizing of blood cells (2) Uses an automated dilution and mixing function for sample processing. (3) Uses a built-in spectrophotometer for measurement of hemoglobin | (1) (2) (3) Same |
| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| | Chempaq XBC Analyzer | Coulter® A^CT™ Diff Analyzer |
| Major Components | (1) Single use cartridge (PAQ) (2) Stationary Reader with docking station (Cradle) (3) Display Screen for test results. | (1) Multi-use system (2) Stationary instrument with sample inlet. (3) Same |
| Type of Aperture for particle sizing | Single-use, disposable, polyester membrane cartridge. | Multiple-use, sapphire membrane. |
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I. Special Control/Guidance Document Referenced (if applicable):
Class II Special Control Guidance Document: Premarket Notification for Automated Differential Cell Counters for Immature or Abnormal Blood Cells Final Guidance for Industry and FDA, December 4, 2001
EP9-A2 Method Comparison and Bias Estimation Using Patient Samples, Approved Standard-Second Edition, NCCLS
EP5A Evaluation of Precision Performance of Clinical Chemistry Device Approved Guideline, NCCLS
EP6-A Evaluation of the Linearity of Quantitative Measurement Procedures, Approved Guideline, NCCLS
EP7-P Interference Testing in Clinical Chemistry, NCCLS
EP10 Preliminary Evaluation of Quantitative Clinical Laboratory Method, NCCLS
H15-A3 Reference and Selected Procedures for the Quantitative Determination of Hemoglobin in Blood; Approved Standard-Third Edition, NCCLS
H4-A5 Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens, Approved Standard-Fifth Edition, NCCLS
Reference method for the enumeration of erythrocytes and leukocytes, ICSH, Clin Lab Haematology, 16(2): 131-138, 1994.
J. Performance Characteristics:
1. Analytical Performance:
a. Accuracy:
Accuracy was determined using the predicate device as comparative method. Readings on the Compaq XBC were made in 3-7 replicates and readings on the predicate device were made in 3 replicates. The data was collected during 15 days using one Compaq XBC Reader and PAQs stemming from 5 different lots. The relative differences were calculated using means of both device readings. The samples were divided into 5 concentration levels of WBC, 4 concentrations levels of LYM, 2 concentrations levels of MON, 5 concentrations levels of GRN and 3 concentrations levels of HGB. The regression analysis is as follows:
| Analyte | Regression | Correlation | Confidence interval slope (+/-) | Confidence interval intercept (+/-) |
| --- | --- | --- | --- | --- |
| WBC | y=1.006x + 0.059 10^{9}/L
n=130 | r=0.99 | 0.012 | 0.094 10^{9}/L |
| LYM | y=0.911x + 0.128 10^{9}/L | r=0.97 | 0.036 | 0.052 10^{9}/L |
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b. Precision/Reproducibility:
Precision was performed on three blood samples (three levels of concentration, 20 replicates) using two readers and one batch of PAQs. The results are as follows:
| WBC concentration (x10^9/L) | Number of replicates | Within-run imprecision SD (x10^9/L) | Within-run imprecision CV (%) |
| --- | --- | --- | --- |
| 1.84 | 20 | 0.13 | 7 |
| 5.43 | 20 | 0.19 | 3.5 |
| 16.43 | 20 | 0.74 | 4.5 |
Within-run imprecision WBC
| Hb concentration (g/dL) | Number of replicates | Within-run imprecision (g/dL) | Within-run imprecision CV (%) |
| --- | --- | --- | --- |
| 6.2 | 20 | 0.18 | 2.9 |
| 15.08 | 20 | 0.24 | 1.6 |
| 17.52 | 20 | 0.44 | 2.5 |
Within-run imprecision Hb
Additional precision was determined by analyzing three concentration levels of a commercial liquid blood control (using one lot) and analyzed on 20 consecutive working days. One Chempaq XBC Reader and one lot of PAQs were used. The results are as follows:
| Control Blood WBC (x10^9/L) | N | Total imprecision SD (x10^9/L) | Total imprecision CV (%) |
| --- | --- | --- | --- |
| 1.51 | 20 | 0.100 | 6.6 |
| 4.77 | 20 | 0.208 | 4.4 |
| 11.84 | 20 | 0.433 | 3.7 |
| Control Blood LYM (x10^9/L) | N | Total imprecision SD (x10^9/L) | Total imprecision CV (%) |
| --- | --- | --- | --- |
| 0.58 | 20 | 0.147 | 25.3 |
| 1.65 | 20 | 0.349 | 21.1 |
| 4.00 | 20 | 0.755 | 18.9 |
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| Control Blood MON (x109/L) | N | Total imprecision SD (x109/L) | Total imprecision CV (%) |
| --- | --- | --- | --- |
| 0.22 | 20 | 0.041 | 18.6 |
| 0.67 | 20 | 0.049 | 7.3 |
| 1.55 | 20 | 0.076 | 4.9 |
| Control Blood GRN (x109/L) | N | Total imprecision SD (x109/L) | Total imprecision CV (%) |
| --- | --- | --- | --- |
| 0.70 | 20 | 0.150 | 21.4 |
| 2.44 | 20 | 0.305 | 12.5 |
| 6.28 | 20 | 0.514 | 8.5 |
| Control Blood Hb (g/dL) | N | Total imprecision SD (g/dL) | Total imprecision CV (%) |
| --- | --- | --- | --- |
| 6.56 | 20 | 0.217 | 3.3 |
| 13.13 | 20 | 0.206 | 1.6 |
| 18.24 | 20 | 0.319 | 1.7 |
## c. Linearity:
A linearity study was performed using 1 venous blood sample which was divided into 2 tubes (low and high samples were prepared). A dilution scheme was outlined and resulted into 11 samples for the diluting scheme. These 11 samples were randomly analyzed on 5 readers. One sample analyzed in 3 replicates. The results were as follows:
| Analyte | Correlation r² | Regression |
| --- | --- | --- |
| WBC | 0.99 | y=1.00x +0.0013x 10⁹/L |
| Hb | 0.99 | y=1.00x +0.0048 mmol/L |
The reportable ranges are as follows:
WBC 0-100 (x10⁹/L)
HB 0-21 (g/dL)
## d. Carryover:
Not applicable.
## e. Interfering Substances:
Interference studies were performed on EDTA, sodium citrate, triglycerides, and bilirubin. No interferences with these substances were identified.
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Interference studies were performed on 6 venous blood samples containing heparin on 5 Readers. Based on the results it was concluded that there is interference of heparin and this substance cannot be used as an anticoagulant for samples used on the Chempaq XBC system.
2. Other Supportive Instrument Performance Data Not Covered Above:
K. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.
L. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
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Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
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Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
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Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
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Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
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With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
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What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
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Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.
