The Cannabinoid Enzyme Immunoassay is a homogeneous enzyme immunoassay with a 20 ng/mL, 50 ng/mL (SHAHSA recommended initial test cutoff concentration), or 100 ng/mL cutoff. The assay is intended for use in the qualitative and semi-quantitative analyses of cannabinoids (THC) in human urine. The assay is designed for professional use with a number of automated clinical chemistry analyzers. The Cannabinoid Enzyme Immunoassay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration and professional judgement should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used.
Device Story
Ready-to-use liquid reagent homogeneous enzyme immunoassay; detects cannabinoids (THC) in human urine. Principle: competition between Δ9-THC-labeled G6PDH enzyme and free drug in urine sample for fixed amount of specific antibody. Absence of free drug allows antibody binding to labeled enzyme, decreasing enzyme activity. Activity measured spectrophotometrically at 340 nm via conversion of NAD to NADH. Used in clinical laboratories with automated chemistry analyzers; operated by laboratory professionals. Provides preliminary analytical results; requires confirmation by GC/MS. Assists clinicians in drug-of-abuse screening.
Clinical Evidence
Bench testing only. Evaluated precision (within-run and run-to-run), sensitivity, accuracy, analytical recovery, and specificity. Accuracy compared against predicate device (n=216) and GC/MS (n=592). Results showed 100% agreement for most samples; one marginal discrepancy noted in THC 100 assay. Analytical recovery demonstrated 98.7% at 37.5 ng/mL and 93.2% at 62.5 ng/mL. Precision CVs generally <3.6%.
Technological Characteristics
Homogeneous enzyme immunoassay; liquid reagent format. Sensing principle: spectrophotometric measurement of G6PDH enzyme activity at 340 nm. Compatible with automated clinical chemistry analyzers. No specific materials of construction or connectivity standards listed.
Indications for Use
Indicated for qualitative and semi-quantitative analysis of cannabinoids (THC) in human urine. Intended for professional use in clinical settings to provide preliminary analytical test results. Requires confirmatory testing via alternative methods like GC/MS.
Regulatory Classification
Identification
A cannabinoid test system is a device intended to measure any of the cannabinoids, hallucinogenic compounds endogenous to marihuana, in serum, plasma, saliva, and urine. Cannabinoid compounds include delta-9-tetrahydrocannabinol, cannabidiol, cannabinol, and cannabichromene. Measurements obtained by this device are used in the diagnosis and treatment of cannabinoid use or abuse and in monitoring levels of cannabinoids during clinical investigational use.
Special Controls
*Classification.* Class II (special controls). A cannabinoid test system is not exempt if it is intended for any use other than employment or insurance testing or is intended for Federal drug testing programs. The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9, provided the test system is intended for employment and insurance testing and includes a statement in the labeling that the device is intended solely for use in employment and insurance testing, and does not include devices intended for Federal drug testing programs (*e.g.,* programs run by the Substance Abuse and Mental Health Services Administration (SAMHSA), the Department of Transportation (DOT), and the U.S. military).
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# AUG 1 5 2002
KC21887
## 510(k) Summary of Safety and Effectiveness
This summary of 510(k) safetv and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
#### Introduction
According to the requirements of 21 CFR 807.92, the following information provides sufficient detail to understand the basis for a determination of substantial equivalence.
#### Submitter name. Address, and Contact
Lin-Zhi International, Inc. 2391 Zanker Road, Suite 340 San Jose, CA 95131-1124 Phone: (408) 944-0360 Fax: (408) 944-0359
Chiu Chin Chang, Ph.D. Contact: VP, R&D
#### Device Name and Classification
| Classification Name: | Enzyme Immunoassay, Cannabinoids,<br>Class II, LDJ (91 Toxicology), 21CFR 862.3870 |
|----------------------|-----------------------------------------------------------------------------------------------|
| Common Name: | Homogeneous enzyme immunoassay for the determination<br>of cannabinoids (THC) level in urine. |
| Proprietary Name: | None |
## Legally Marketed Predicate Device(s)
Lin-Zhi International, Inc.'s Cannabinoid Enzyme Immunoassay is substantially equivalent to the Cannabinoid (THC) Enzyme Immunoassay (By DRJMicrogenics Corp.), cleared under premarket notification K943998.
LZI's Cannabinoid Enzyme Immunoassay is identical or similar to its predicate in terms of intended use, method principle, device components, and clinical performance.
#### Device Description
LZI's Cannabinoid Enzyme Immunoassay is a ready-to-use liquid reagent, homogeneous enzyme immunoassay. The assay uses specific antibody that can detect cannabinoids (THC) in human urine with minimal cross-reactivity to various, common prescription drugs and abused drugs.
The assay is based on competition between Δ - THC-labeled glucose-6-phosphate dehydrogenase (G6PDH) enzyme, and free drug from the urine sample for a fixed
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amount of specific antibody. In the absence of free drug from the urine sample the specific antibody binds to the drug labeled with G6PDH enzyme causing a decrease in enzyme activity. The G6PDH enzyme activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.
## Intended Use
The Cannabinoid Enzyme Immunoassay is a homogeneous enzyme immunoassay with a 20 ng/mL, 50 ng/mL (SAMHSA recommended initial test cutoff concentration), or 100 ng/mL cutoff. The assay is intended for use in the qualitative and semi-quantitative analyses of cannabinoids (THC) in human urine. The assay is designed for professional use with a number of automated clinical chemistry analyzers.
## Comparison to Predicate Device
LZI's Cannabinoid Enzyme Immunoassay is substantially equivalent to other products in commercially distribution intended for similar use. Most notably it is substantially equivalent to the currently, commercially marketed Cannabinoid (THC) Enzyme Immunoassay (K943998) by Diagnostic Reagents, Inc. (DRI, now Microgenics Corporation)
The following table compares LZI's Cannabinoid Enzyme Immunoassay with the predicate device, DRI's Cannabinoid (THC) Enzyme Immunoassay.
Similarities:
- . Both assays are for qualitative and semi-quantitative determination of cannabinoids in human urine.
- Both assays use the same method principle, and device components. .
- Both assays can be used with a 20 ng/mL, 50 ng/mL (Cutoff level per . recommendations of The Substance Abuse and Metal Health Services Administration, or SAMHSA), or 100 ng/mL cutoff.
- The same 5 calibrators were used for qualitative analyses of the assay. .
Differences:
- In the semi-quantitative analysis of cannabinoids concentration in urine. LZI's . Cannabinoid Enzyme Immunoassay uses a specified 5 calibrators set for each cutoff assay. DRI's Cannabinoid (THC) EIA used the same 5 calibrators for both qualitative analyses and the semi-quantitative analyses purposes.
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## (Comparison to Predicate Device, continued)
| Feature | DRI's Cannabinoid (THC) EIA | | | LZI's Cannabinoid EIA | | | |
|-----------------------|--------------------------------------|----------------|-----------------------------|------------------------------------------------------------------------------------|-----------------|--------------------------------|-------------------------------------|
| Within Run Precision: | | | | (Illustrated with THC 50 assay results) | | | |
| Qualitative: | Mean Rate | SD | % CV | Mean Rate | SD | % CV | |
| | Negative | 287 | 1.0 | Negative | 318.7 | 2.2 | 0.68 |
| | 20 ng/mL | 317 | 0.9 | 20 ng/mL | 346.3 | 2.5 | 0.72 |
| | 50 ng/mL | 387 | 0.9 | 50 ng/mL | 398.7 | 3.5 | 0.87 |
| | 100 ng/mL | 447 | 0.9 | 100 ng/mL | 456.0 | 3.3 | 0.73 |
| | 200 ng/mL | 472 | 0.5 | 200 ng/mL | 475.1 | 1.9 | 0.39 |
| Semi-quantitative: | No data available. | | | Mean Conc | SD | % CV | |
| | | | | 37.5 ng/mL | 38.3 | 0.8 | 2.12 |
| | | | | 50 ng/mL | 50.0 | 1.4 | 2.78 |
| | | | | 62.5 ng/mL | 65.1 | 1.9 | 2.91 |
| Run-To-Run Precision: | | | | (Illustrated with THC 50 assay results) | | | |
| Qualitative: | Mean Rate | SD | % CV | Mean Rate | SD | % CV | |
| | Negative | 287 | 1.0 | Negative | 320.5 | 3.1 | 0.96 |
| | 20 ng/mL | 319 | 0.7 | 20 ng/mL | 347.6 | 2.3 | 0.66 |
| | 50 ng/mL | 388 | 1.0 | 50 ng/mL | 399.8 | 3.9 | 0.97 |
| | 100 ng/mL | 449 | 1.2 | 100 ng/mL | 457.6 | 4.0 | 0.88 |
| | 200 ng/mL | 473 | 0.8 | 200 ng/mL | 477.1 | 3.5 | 0.73 |
| Semi-quantitative: | No data available. | | | Mean Conc | SD | % CV | |
| | | | | 37.5 ng/mL | 37.1 | 0.9 | 2.41 |
| | | | | 50 ng/mL | 48.4 | 1.5 | 3.02 |
| | | | | 62.5 ng/mL | 63.9 | 2.3 | 3.59 |
| Sensitivity: | 10 ng/mL | | | 5 ng/mL | (THC 20 assay); | | |
| | | | | 7.5 ng/mL | (THC 50 assay); | | |
| | | | | 15 ng/mL | (THC 100 assay) | | |
| Accuracy: | Vs. GC/MS* (n = 592) | | | Vs. DRI s Cannabinoid EIA (n = 216) | | | |
| | THC 20 assay | THC 50 assay | THC 100 assay | THC 20 assay | THC 50 assay | THC 100 assay | |
| Positive Samples: | No data | 100% Agreement | 6 borderline negative found | 100 % Agreement | 100 % Agreement | 98.3 % (1 marginal discrepant) | |
| Negative Samples: | No data | 100% Agreement | 100% Agreement | 100 % Agreement | 100 % Agreement | 100 % Agreement | |
| Analytical Recovery: | | | | (Illustrated with THC 50 assay) | | | |
| | Qualitative: No data available | | | 100 % accuracy on positive vs. negative tests | | | |
| | Semi-quantitative: No data available | | | Quantitate within ±12% of the nominal concentration between 10 ng/mL and 95 ng/mL. | | | |
| | | | | Average 98.7 % recovery at 37.5 ng/mL level (Cutoff - 25%) | | | |
| | | | | Average 93.2 % recovery at 62.5 ng/mL level (Cutoff + 25%) | | | |
| Specificity: | | | | See attached DRI s Cannabinoid (THC) EIA package insert | | | Comparable to the predicate device. |
#### Performance Characteristics
* A 15 ng/mL cutoff for GC/MS was used for comparison.
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## Conclusion
LZI's Cannabinoid Enzyme Immunoassay was evaluated for several performance characteristics including precision, sensitivity, accuracy, analytical recovery, and specificity. All the studies showed acceptable results when compared to the predicate device.
We trust the information provided in this Premarket Notification [510(k)] submission will support a determination of substantial equivalence of the LZI's Cannabinoid Enzyme Immunoassay to other cannabinoid test systems currently marketed in the United States.
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#### DEPARTMENT OF HEALTH & HUMAN SERVICES
Image /page/4/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized image of an eagle with three lines representing its body and wings. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the eagle.
Food and Drug Administration 2098 Gaither Road Rockville MD 20850
## AUG 1 5 2002
Chiu Chin Chang, Ph.D. VP. R & D Lin-Zhi International, Inc. . 2391 Zanker Road. Suite 340 San Jose, CA 95131-1124
Re: k021887
> Trade/Device Name: Cannabinoid Enzyme Immunoassay Regulation Number: 21 CFR 862. 3870 Regulation Name: Cannabinoid test system Regulatory Class: Class II Product Code: LDJ Dated: June 5, 2002 Received: June 7, 2002
Dear Dr. Chang:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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Page 2 -
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device. please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsma/dsmamain.html".
Sincerely yours,
Steven Sutman
Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory-Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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# Premarket Notification -
## Indications for Use Statement
510(k) Number (if known): K021887
## Device Name: Cannabinoid Enzyme Immunoassay
#### Indications for Use:
The Cannabinoid Enzyme Immunoassay is a homogeneous enzyme immunoassay with a 20 ng/mL, 50 ng/mL (SHAHSA recommended initial test cutoff concentration), or 100 ng/mL cutoff. The assay is intended for use in the qualitative and semi-quantitative analyses of cannabinoids (THC) in human urine. The assay is designed for professional use with a number of automated clinical chemistry analyzers.
The Cannabinoid Enzyme Immunoassay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration and professional judgement should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used.
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Concurrence of CDRH, Office of Device Evaluation (ODE)
Prescription Use (Per 21 CFR 801.109)
OR
Over-The-Counter Use
(Optional Format 1-2-96)
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Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
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.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
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?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
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.
Where do you find a device's intended use without opening the PDF?
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
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
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.
6. Collections
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.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
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.
8. Chart view
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.