What does the 50 ng/mL cut-off mean?

The strip reports positive when THC metabolite in urine is at or above 50 ng/mL, the level most workplace and lab screens use. Below that, it reads negative.

How long after use can it detect THC?

Typically 1 to 5 days after occasional use. Heavy or daily users can test positive for weeks, so retest over several days if you need to track clearance.

How do I read the result?

Two lines, including a faint control line, means negative. A single control line means positive. No control line means the test failed and should be repeated.

Is this the same as a lab test?

No. It is a qualitative screening strip. A positive result should be confirmed by a certified lab test before anyone acts on it.

Ten individually wrapped test strips in the 10-pack, model WDTH-114. Check the pack for any included cups or instructions.

The best new price is $5.99 for the 10-pack at Amazon as of November 6, 2026. Only one store lists it new, so watch that listing for changes.

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Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level

Best price now

$5.99at AmazonObserved at 7:02 PM

Prices are checked against each store and labelled with when.

Visit Amazon

Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level

Best price now

$5.99at AmazonObserved at 7:02 PM

Prices are checked against each store and labelled with when.

Visit Amazon

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Our take on the Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level

This is a 10-pack of Prime Screen marijuana urine test strips, model WDTH-114, made by Wondfo. Each strip screens urine for THC metabolites at a 50 ng/mL cut-off, the threshold most workplace and lab screens use. Results are read as lines in a few minutes with no lab needed. The best new price is $5.99 for the 10-pack at Amazon as of November 6, 2026, and only one store lists it new, so there is no recent price range to compare against.

Best forAt-home self-checks before a drug screenPeople monitoring THC clearance after stoppingHouseholds that want several tests on handQuick, private screening without a lab

Pros

50 ng/mL cut-off matches common lab screening thresholds
10 tests per pack, so you can retest over several days
Simple dip-and-read strip with results in minutes
Made by Wondfo, a large maker of rapid diagnostic tests
Low cost per test at $5.99 for the pack

Cons

Urine only; not for saliva or hair testing
A line result is qualitative, not a measured level
Detection window varies with dose, frequency and body fat
Not a substitute for a certified lab confirmation

Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level prices at every store

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$5.99Observed at 7:02 PM
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Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level price history

Lowest price we've seen: $5.99 on Nov 7 at Amazon. Tracked across 1 store since Nov 7.

What reviewers say

4.6 / 573 ratings

Rated 4.6 out of 5 from 73 ratings. Buyers mostly report the strips are easy to use and give clear lines, and many use them to track THC clearance over days. Some question faint lines or want more guidance on reading results.

What people mention

Ease of usePraisedBuyers say the strips are simple to dip and read without instructions.
Result clarityMixedMost find the lines clear, but some say faint lines are hard to judge.
ValuePraisedOwners like getting 10 tests for a low price.
Detection trackingPraisedUsers test every few days to watch THC clear after stopping.
Cut-off levelMixedThe 50 ng/mL threshold suits lab-style screening, but a faint line near it leaves some unsure.

About the Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level

What is Cannabinoids / Marijuana (THC) Cannabinoids are hallucinogenic agents derived from the flowering portion of the hemp plant. The active ingredient in Cannabinoids, THC & Cannabinol can be metabolized and excreted as 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid with a half-life of 24 hours. They can be detected for 1 to 5 days after use. Smoking is the primary method of use of Cannabinoids/cannabis. Higher dose use by abusers produces central nervous system effects, altered mood and sensory perceptions, loss of coordination, impaired short-term memory, anxiety, paranoia, depression, confusion, hallucinations, and increased heart rate. A tolerance to the cardiac and psychotropic effects can occur, and withdrawal syndrome products restlessness, insomnia, anorexia, and nausea.

Specifications

size: 10 TESTSource
Pack size: 10 PackSource
Model number: WDTH-114Source
Brand: Prime ScreenSource

Questions and answers

What does the 50 ng/mL cut-off mean?: The strip reports positive when THC metabolite in urine is at or above 50 ng/mL, the level most workplace and lab screens use. Below that, it reads negative.
How long after use can it detect THC?: Typically 1 to 5 days after occasional use. Heavy or daily users can test positive for weeks, so retest over several days if you need to track clearance.
How do I read the result?: Two lines, including a faint control line, means negative. A single control line means positive. No control line means the test failed and should be repeated.
Is this the same as a lab test?: No. It is a qualitative screening strip. A positive result should be confirmed by a certified lab test before anyone acts on it.
What is in the box?: Ten individually wrapped test strips in the 10-pack, model WDTH-114. Check the pack for any included cups or instructions.
When is it cheapest?: The best new price is $5.99 for the 10-pack at Amazon as of November 6, 2026. Only one store lists it new, so watch that listing for changes.
Where is the Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level cheapest?: At Amazon, for $5.99, as of our latest check.
What do buyers say about the Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level?: Rated 4.6 out of 5 from 73 ratings.
Where can I buy the Prime Screen Marijuana Urine Drug Test Kit with 50 ng/mL cut-off level?: 2 stores we checked sell it, including Amazon, Walmart.