4 Key Components of a Validation Document for Cannabis Pathogen Testing

Here’re 4 key factors cultivators should evaluate when choosing reliable pathogen testing services, ensuring accurate results and safeguarding their crops.

When it comes to pathogen testing, whether in cannabis cultivation or controlled environment agriculture (CEA), accuracy is everything. A key tool for cultivators to guarantee reliable testing services is a validation document. Here's a quick look at the four key components that should be included in any validation document.

Key components of a validation document

Understanding the core components of a validation document helps cultivators make informed decisions when selecting a testing service. Here are the key experiments and metrics included in a complete validation:

1. Sensitivity/Limit of Detection (LoD)

The sensitivity, or limit of detection, refers to the lowest concentration of a pathogen that the test can detect with 95% accuracy. This is particularly important in pathogen prevention, as it helps cultivators catch infections early before they spread and devastate crops.

A strong LoD analysis will show how well the test performs at decreasingly low pathogen concentrations. If the validation document lacks this analysis, the test may not be sensitive enough to allow early detection.

Table shows the results from studies performed to determine the LoD of TUMI Genomics HLVd qRT-PCR assay. The identified LoD is indicated in blue.

2. Inclusivity

This analysis evaluates whether the test can identify different variants of a given pathogen. For example, hop latent viroid exists as a variety of sequence variants. It is critical to ensure that the evaluated test can detect the vast majority of these variations,The inclusivity study ensures the test won’t miss a variant, reducing the risk of false negatives.

Table shows the number of annotated HLVd genomes showing well-represented mismatches with regions targeted by the primer used in the TUMIGlow-HLVd assay.

3. Cross-Reactivity

You want a test to be specific to the target pathogen, and not throw a positive result if contaminating organisms (like unrelated bacteria or fungus) are in the sample. A cross-reactivity analysis ensures the test won’t return false positives by mistaking other contaminants for the target pathogen. This test is critical for all diagnostic tests. 

When running a cross-reactivity study it's essential to evaluate whether the test can differentiate between the target pathogen and other similar/common organisms that might be present in the sample. This involves testing the assay against closely related pathogens, non-pathogenic strains, and common pathogens found in the environment.  Cross-reactivity can lead to false positives, so confirming that the test only detects the target pathogen without interference from non-target species is crucial for maintaining diagnostic accuracy and reliability.

The table shows the identity of each tested microorganism and the percent cross-reactivity with the primer/probe sets used to target the HLVd genome and the cannabis genome. Included in this graph are viral, fungal, and bacterial pathogens.

4. Accuracy

Accuracy determines how often the test correctly identifies the presence or absence of a pathogen. It combines the false positive and false negative rates. A good validation document will show at least 95% agreement between the test results and a high-sensitivity comparison method. 

As shown by the table below, the TUMIGlow-HLVd assay was performed with 99.1% accuracy compared to PCR. The TUMIGlow test detected 100% of HLVd(+) samples down to ~20 viroid copies/μL. Additionally, no false positive or false negative results were obtained.

Vet Your Testing Services

A validation document with these variables helps ensure that diagnostic tests are effective tools in terms of crop health and economic return. Especially in an industry where crop quality and yield optimization are top priorities, using incomplete or unreliable tests can lead to missed infections, lower yields, and wasted resources.

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About TUMI Genomics

TUMI Genomics is advancing cannabis cultivation by bringing biological insights to help commercial growers thrive. Through comprehensive preventative solutions, superior pathogen diagnostics, and AI-driven insights, TUMI Genomics is helping cultivators start clean and stay clean. The unrivaled diagnostics, transparent validation and industry-leading pathogen detection innovations provided by TUMI Genomics are raising the standards of commercial cannabis cultivation. The team at TUMI Genomics is composed of deeply experienced Ph.D. molecular biologists, bioinformaticians, business strategists, and accomplished serial entrepreneurs.

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