What Does "Not Detected" Mean on a Test Report? A 2026 Guide to Detection and Quantification Limits
JRQ consumer verification guide Published: November 6, 2026
When you get a test report, many phrases are hard to read. The question people ask most often is: when it says “not detected,” does that mean there is none at all? The answer first: no. “Not detected” does not mean the amount is zero. JRQ does not name brands. This guide only explains how to read these terms so you can check a report yourself.
Limit of detection and limit of quantification: how to read “not detected” and “below the limit of quantification”
Answer first: “Not detected” does not mean the amount is zero. It only means the result is below the method’s limit of detection (LOD).
The limit of detection is the lowest level at which the method can confirm that something is there. Below this level, the method cannot tell the difference between “none” and “there is some, but too little to measure.” As an analogy, the limit of detection is like the lowest weight a scale can sense. If something is lighter than that, the scale gives no response.
The limit of quantification (LOQ) is the lowest level at which the method can give a reliable number. It is usually higher than the limit of detection. When a result falls between the two, the method can confirm that something is there, but cannot give a reliable number. The report should then say “below the limit of quantification.”
So the two phrases on a report mean different things: “not detected” means below the limit of detection; “below the limit of quantification” means something may have been detected, but the number is not reliable. Neither phrase means the amount is zero.
Symbols are also common on reports: the abbreviation “ND” (not detected) means not detected; “<××” means the result is below the value ××. Readers should check whether the number after “<” refers to the limit of detection or the limit of quantification, and the report should say so. Within the same report, different test items may have different limits of detection. Check each item separately; do not use the value for one item to interpret another.
JRQ standard JRQ-D-016 Labeling Standard for Limits of Quantification and Detection says that a result without a value must not be treated as zero or as passing. When reading a report, also check whether the test method and the value of the limit of detection or limit of quantification are stated. If a report says “not detected” but does not give the limit of detection, that phrase is less useful for checking.
What a report should state, and how to compare results
A report that can be checked states at least four things: the test method, the value of the limit of detection or limit of quantification, whether the sample is a raw material or a finished product, and the lot number. If any one is missing, readers cannot complete the check. A report that only says “pass” and lists nothing else cannot be checked.
The test method should state the specific name. For example, high-performance liquid chromatography (HPLC) should include the method basis. Saying only “tested by a standard method” without naming the method is the same as not writing it. The values for the limit of detection and limit of quantification must be read together with the test method, because different methods can produce very different values.
The report should state whether the sample is a raw material or a finished product. Purity data for a raw material is not the same as the content per unit in a finished product. JRQ standard JRQ-D-005 Certificate of Analysis Disclosure Standard requires the disclosed report to match the labeled item; a raw material report cannot be used in place of a finished product report.
The lot number links the report to the specific product. The lot number on the bottle, the outer box, and the report should be the same. JRQ-D-004 Lot Labeling Standard can be used as a reference. If the lot numbers do not match, the report is only “a reference from one test,” and it does not prove anything about the bottle in your hand.
Results from different laboratories or different methods cannot be compared directly. Different methods can have very different limits of detection; different laboratories also have differences in procedure. One report may say “not detected” and another may give a content value ××. This may simply be because the two methods have different precision, not a contradiction. Before comparing, first check whether the methods are of the same type and whether the limits of detection are in the same range.
Verification checklist
| Item to check | Where to look | What adequate information looks like | Warning signs |
|---|---|---|---|
| Test method | Report body or method column | States the specific method name and basis | Only says “standard method” without naming it |
| Limit of detection / limit of quantification | Report body or notes column | Has a value and unit, and matches the method | Says “not detected” but does not give the limit of detection |
| Sample type | Report header or sample information column | States whether it is a raw material or finished product; for finished products, states the dosage form | Only gives the ingredient name, without stating raw material or finished product |
| Lot number | Report header, and compare with bottle and outer box | Same in all three places, clear and readable | Lot number missing, unclear, or does not match |
| Test item | Results table | Lists each item and its determination | Only the word “pass,” with no item details |
| Testing institution | Report footer | Has institution name and report number | Institution name covered or removed; number missing |
| Report date | Report header or footer | Matches the production timeline of the lot number | Date missing, or earlier than production date |
Common misconceptions
- Misconception 1: “Not detected” means the amount is zero. Note: It only means the result is below the limit of detection; it does not mean the amount is zero.
- Misconception 2: A thicker report is more trustworthy. Note: What matters is whether the basic information is complete; thickness proves nothing.
- Misconception 3: A report that says “pass” is enough to be reassuring. Note: A report with only “pass” lacks test items and method, and cannot be checked.
- Misconception 4: If raw material purity is high, the finished product content must be high. Note: Raw material purity is a result for the raw material; it is not the same as the content per unit in the finished product.
- Misconception 5: Values from different reports can be compared directly. Note: When methods differ or limits of detection differ, comparing values has no meaning.
Related JRQ standards
- JRQ-D-016 Labeling Standard for Limits of Quantification and Detection: sets out the limit of detection, limit of quantification, and how results are written. A result without a value must not be treated as zero or as passing.
- JRQ-D-005 Certificate of Analysis Disclosure Standard: sets out that disclosed test reports must match the labeled item, be genuine, and be checked against the label.
- JRQ-D-004 Lot Labeling Standard: sets out where lot numbers appear, their readability, and how they connect to public materials.
- JRQ-D-002 Purity Labeling Standard: distinguishes purity statements for raw materials from content statements for finished products; use as a reference when reading reports.
Scope of this guide
This guide only explains how to read and check test reports. It does not evaluate the efficacy of any ingredient, and it does not recommend or certify any specific product. If you are taking medication, have a chronic condition, or are pregnant or breastfeeding, consult a doctor or pharmacist before buying.
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