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PRO-LAB

PRO-LAB RA100

Short-term liquid scintillation radon test kit

  • Short-term kit
  • 48 to 96 hours
  • Liquid scintillation
  • Lab fee extra

Best for, and skip if

Best for you if

  • You want two detectors in one kit, so the result is the average of two side-by-side measurements.
  • You can keep the house closed for two to four days and the 12 hours before.

Skip it if

  • You want the lab fee inside the kit price; PRO-LAB has you pay it when you return the detectors.
  • You may not be home to cap the detectors within 96 hours of opening them; the instructions treat a longer exposure as invalid.
See how it compares: Best radon test kits, every kit comparedWho it fits
  • PRO-LAB RA100

Photos: PRO-LAB

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  • Test length48 to 96 hours
  • MethodLiquid scintillation
  • Lab feeExtra
  • Every figure checked against the specifications PRO-LAB publishes
  • Independent test results shown the same way for every product, unranked
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About this item

As PRO-LAB states it

  • How it measures: Liquid scintillation detectors with silica gel desiccant, laboratory analysis
  • Exposure time: 48 hours to 96 hours
  • Lab fee: Paid separately
  • Power: None needed
  • Units: pCi/L

PRO-LAB's short-term radon kit, model RA100, holds two liquid scintillation detectors that you uncap side by side on the lowest livable level of your home for at least 48 and no more than 96 hours, as PRO-LAB's instructions set out, then cap and mail to PRO-LAB with the lab fee, which is paid separately. PRO-LAB says standard results are mailed within a week of receipt, with an express service for home sales. Its own pages give other exposure times too: the FAQ lists the RA100 at 48 to 168 hours, and the product description says 96 hours.

What you get

PRO-LAB's page describes two desiccated short-term detectors with caps and a pre-paid postage envelope for the return. Its description asks you to complete the data card, and its instructions to send a completed test location form with the detectors. Questions go to PRO-LAB's environmental testing specialists by phone.

In the box and running costs

How it works

What it measures and how

The sensor, the sampling and the readings, then who has checked it

How it works

In our words, from the maker's documents

PRO-LAB describes its detectors as liquid scintillation, short-term detectors that contain a patented silica gel desiccant to remove moisture. PRO-LAB does not say what else the detectors contain. The EPA names charcoal liquid scintillation devices among the detectors most commonly used for short-term testing. Each detector collects radon passively while it sits uncapped, and the measurement is made later, at the laboratory. PRO-LAB's FAQ describes the routine: remove the caps to start, replace them when the exposure time is over, return the canisters, and do not take out what is inside them.

What sets this kit apart is that it contains two detectors. PRO-LAB says the pair lets you run a side-by-side test, its instructions place the two six inches apart, and its guidance compares the average of the two results with 4.0 pCi/L. The EPA describes the same idea for home sales: two short-term tests at the same time in the same location, using the average of the two results.

PRO-LAB's instructions set the exposure window: leave the two detectors uncapped and undisturbed in the same place for at least 48 hours and no more than 96 hours, and write down the start and end dates and times to the minute. They say the results will be invalid if the detectors are open for less than 48 hours or more than 96, and that you would then need another kit to repeat the test. The EPA counts any test from two to 90 days as short-term and says all radon tests should run for a minimum of 48 hours, so the RA100 sits at the short end of that range.

PRO-LAB's own pages do not all give the same window. The product description on the kit's page says to leave the detectors out for a period of 96 hours. PRO-LAB's FAQ says its short-term kit is designed for an exposure time of 48 to 96 hours, but its answer on minimum and maximum exposure times lists the RA100 at a minimum of 48 hours and a maximum of 168 hours, seven full days, and says a sample exposed for less than 48 hours gets a report with no radon level, marked as underexposed. This page uses the instructions' 48 to 96 hours: they are the steps PRO-LAB publishes for running the test, and they are the stricter limit, treating anything past 96 hours as invalid. If the instructions in your box say otherwise, follow them, or call PRO-LAB before you start.

PRO-LAB also sells a long-term kit, model RL116, and describes the RA100 as suited to initial screening. The EPA's view is similar: a long-term test, more than 90 days, is more likely than a short-term one to tell you a home's year-round average, because radon levels vary from day to day and season to season.

What the result means follows the EPA's steps rather than the kit's. The EPA says to take a follow-up test when a short-term result is at or above 4 pCi/L, either a long-term test or a second short-term test, and to consider fixing between 2 and 4 pCi/L. Two detectors side by side give two readings to average, but the result is still a measurement of two to four days, not of a year.

What the manufacturer says

PRO-LAB's own statements, attributed

  • PRO-LAB saysPRO-LAB states that standard results are mailed within one week of the lab receiving the detectors.
  • PRO-LAB saysPRO-LAB states on the kit's page that an express service for real estate transactions returns results within 48 hours (2 business days) of receipt; call PRO-LAB for details.
  • PRO-LAB saysPRO-LAB describes its detectors as using patented silica gel desiccants to remove moisture so results are accurate and reliable.
  • PRO-LAB saysPRO-LAB states that email or text notifications tell you when your sample has been received, and that you can view and print your results in the PROLAB Test Kits app.
  • PRO-LAB saysPRO-LAB states that registering the kit online is not required for the analysis, and that every report is emailed or mailed once the analysis is complete.
  • PRO-LAB saysPRO-LAB states that it recommends a radon test every year.

These are PRO-LAB's own statements, attributed to it. They are not our findings, and we have not tested this product ourselves.

Independent evidence

Who checks a device like this

C-NRPP's consumer evaluation covers electronic monitors, not laboratory-analyzed test kits, so it has no result for PRO-LAB RA100. A kit's result comes from the laboratory that analyzes it. Where the maker names that laboratory, or the page cites the National Radon Safety Board's lists of approved devices and accredited laboratories for it, the “How it works” panel and “Questions people ask” say so.

NRSB lists
NRSB's Accredited Radon Laboratories list (June 2026) includes Pro-Lab Inc, Weston, FL, ARL0028, accredited for 12191 Beckman Ready Rad Liquid Scintillation Vial and 10401 Pro Lab Alpha Track, ARL expiration 3/30/2027. PRO-LAB does not name the vial its RA100 uses, so this records the laboratory, not the kit. Checked October 8, 2026.

PRO-LAB RA100

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Specifications

Specifications

Every figure as the maker states it

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The maker's figures

Type
Short-term test kit, two liquid scintillation detectors, mail-in
How it measures
Liquid scintillation detectors with silica gel desiccant, laboratory analysis
Exposure time
48 hours to 96 hours
Lab fee
Paid separately
Power
None needed
Units
pCi/L

What is in the box

PRO-LAB's page describes two desiccated short-term detectors with caps and a pre-paid postage envelope for the return. Its description asks you to complete the data card, and its instructions to send a completed test location form with the detectors. Questions go to PRO-LAB's environmental testing specialists by phone.

PRO-LAB's FAQ says it does not send replacements for lost prepaid mailers; if yours goes missing, you can still send the kit to the address on the information form or to PRO-LAB's physical address. The same FAQ says registering the kit online is a fast way to see results but is not required, and that reports are emailed or mailed either way. PRO-LAB's kit page and FAQ state no warranty for the kit.

What it costs to run

The lab fee is not in the kit price. PRO-LAB's instructions list two lab services, standard with results within 7 days and express in 3 business days for a larger fee, and take payment by money order, check or credit card (Visa, Mastercard, Discover or AMEX) sent with the detectors. Return postage is prepaid for the standard service; express samples must go by an overnight carrier, which is a shipping cost of its own. Check the current fees in PRO-LAB's instructions before you buy.

New Jersey adds a fee. PRO-LAB's FAQ says New Jersey residents pay an additional fee that goes to the New Jersey Department of Environmental Protection, an administrative fee required for all samples collected in the state.

If you would rather pay for the analysis up front, PRO-LAB's kit list includes a short-term kit with lab analysis included, SKU RA400. There is nothing to power and no subscription. If the average is at or above 4 pCi/L, the EPA's next step is a follow-up test, which may mean a second short-term kit or a long-term kit such as PRO-LAB's RL116.

Fit and setup

Who it fits, and how to use it

The fit, then setup and placement as the guidance asks

Who it fits

Good fit if, and look elsewhere if

Good fit if

  • You want two detectors in one kit, so the result is the average of two side-by-side measurements.
  • You can keep the house closed for two to four days and the 12 hours before.
  • You want return postage prepaid for the standard lab service.
  • You want to know when the lab has your sample and to read the results online or in an app.
  • You want the option of an express result during a home sale, after checking your state's rules.

Look elsewhere if

  • You want the lab fee inside the kit price; PRO-LAB has you pay it when you return the detectors.
  • You may not be home to cap the detectors within 96 hours of opening them; the instructions treat a longer exposure as invalid.
  • You want express results without arranging overnight shipping yourself.
  • You want to follow radon over weeks or months.
  • Your state requires a certified tester for a home sale.

Setup and placement

5 steps

  1. PRO-LAB's first step is closed-house conditions: close all windows and doors for at least 12 hours before testing and keep them closed except for normal entry and exit. Do not run fans, whole-house fans or fireplaces; run the furnace and central heating or air conditioning normally; run a window air conditioner with its vent closed or in recycle mode; and keep an installed radon mitigation system running. PRO-LAB also says not to test during severe weather. Its FAQ adds that closed-house conditions cover every door and window in the home, attic and basement windows included.
  2. Placement, in PRO-LAB's terms: the lowest livable level of the home, away from drafts, vents, doors and windows, and not in a kitchen, laundry room or closet, in direct sunlight or near a heat source. Put the two uncapped detectors on a flat surface at least two feet above the floor and three feet from any outside wall, six inches from each other, and record the start date and the exact time in hours and minutes. PRO-LAB's FAQ defines the lowest livable level as the lowest floor where someone in the household spends six or more hours a day, seven days a week, whether that is the basement or a floor above it.
  3. To end the test, put the caps back on both detectors within the 48 to 96 hours and record the end date and time. PRO-LAB asks for the detectors to go into the prepaid envelope within 24 hours of the end of the test, with the completed test location form and payment. For express results, the instructions say to send the sample by an overnight carrier such as FedEx or UPS, and that express samples can only be received Monday to Friday; the FAQ says express and overnight shipments go to PRO-LAB's street address in Weston, Florida, not its PO box.
  4. The EPA's placement guidance is close to PRO-LAB's: the lowest lived-in level, a room used regularly but not the kitchen or bathroom, at least 20 inches above the floor, away from drafts, high heat, high humidity and exterior walls. PRO-LAB's two feet above the floor clears the EPA's 20 inches.
  5. The EPA describes closed-house conditions as keeping all windows closed, keeping doors closed except for normal entry and exit, and not running fans or other machines that bring in air from outside, and says interference with the test or those conditions will invalidate the result. For a short-term test lasting less than four days, it also says to close windows and outside doors at least 12 hours before the test begins, and not to run a two- or three-day test during unusually severe storms or periods of unusually high winds. PRO-LAB asks for the same 12 hours whatever the length of the test.

For where any radon test or monitor should sit in a home, see where to place a radon test.

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Questions

Questions people ask

6 questions about the PRO-LAB RA100, answered

Asked about the RA100

How long do I leave the RA100 detectors out?

Follow PRO-LAB's instructions: at least 48 hours and no more than 96 hours, uncapped and undisturbed, with the start and end times written down. The instructions say a shorter or longer exposure makes the results invalid and means buying another kit to repeat the test.

PRO-LAB's other pages give different figures. The product description says 96 hours; the FAQ's answer on exposure times lists the RA100 at 48 to 168 hours, seven full days, while the same FAQ says the short-term kit is designed for 48 to 96 hours. Where they differ, the instructions are the stricter limit, so plan to cap the detectors by the 96-hour mark.

What is a liquid scintillation radon detector?

It is a passive detector that is analyzed by a laboratory after exposure, rather than one that shows a reading. The EPA names charcoal liquid scintillation devices among the detectors most commonly used for short-term testing. PRO-LAB's own description of its detectors names liquid scintillation and a patented silica gel desiccant, which it says removes moisture so results are accurate and reliable; it does not say what else they contain.

Why are there two detectors, and what if the results differ?

PRO-LAB says the two detectors are for side-by-side testing, placed six inches apart, and its guidance works from the average of the two: if the average is 4.0 pCi/L or higher, it says to take action to reduce radon. The EPA describes two short-term tests at the same time, averaged, as one of the options for a home sale.

The EPA's own next step after a first short-term result at or above 4 pCi/L is a follow-up test, long-term or a second short-term test, before deciding to fix.

How long until I get results?

PRO-LAB says standard results are mailed within one week of receipt, and its instructions and FAQ both give 7 days for the standard service. For express results its pages differ: the kit's page says within 48 hours (2 business days) of receipt, the instructions say 3 business days, and the FAQ says 2 days. Express samples must travel by overnight carrier and can only be received on weekdays.

PRO-LAB says email or text notifications confirm when your sample arrives, and that you can view and print results in its app. Add mailing time both ways to any of these figures.

Who analyzes the detectors?

PRO-LAB's instructions send the detectors to PRO-LAB in Weston, Florida, and its site says all analyses are performed by PRO-LAB or by laboratories it recognizes as licensed, certified or accredited.

NRSB publishes a list of the radon laboratories it has accredited to analyze specific approved devices. Its June 2026 list includes Pro-Lab Inc of Weston, Florida, with an accreditation expiry of March 30, 2027. NRSB accredits a laboratory for named devices, and PRO-LAB does not say which listed device its RA100 detectors are, so the listing describes the laboratory rather than this kit.

Can I use it for a home sale?

PRO-LAB offers express results for real estate transactions. Check your state's rules before relying on any do-it-yourself kit for a sale. The EPA describes the testing options and conditions for a sale, and our guide to buying a house with radon, under Guides, sets them out step by step.

What to do next

Updated October 8, 2026