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PRO-LAB

PRO-LAB RA400

Short-term liquid scintillation radon test kit, lab fee included

  • Short-term kit
  • 48 to 96 hours
  • Liquid scintillation
  • Lab fee included
  • PRO-LAB RA400
  • PRO-LAB RA400, photo 2 of 4
  • PRO-LAB RA400, photo 3 of 4
  • PRO-LAB RA400, photo 4 of 4

Photos: PRO-LAB

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  • Test length48 to 96 hours
  • MethodLiquid scintillation
  • Lab feeIncluded
  • 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, two detectors side by side, laboratory analysis
  • Exposure time: 48 hours to 96 hours
  • Lab fee: Included in the kit
  • Power: None needed
  • Units: pCi/L

The RA400 is PRO-LAB's short-term radon test kit with the laboratory analysis included: two liquid scintillation detectors that you uncap side by side, cap again when the test ends and mail to PRO-LAB, which says results come within 7 days. PRO-LAB's FAQ gives its short-term kit an exposure time of 48 to 96 hours; the RA400's own store page states none. The National Radon Safety Board's June 2026 list of accredited radon laboratories includes Pro-Lab Inc of Weston, Florida.

What you get

The RA400 box PRO-LAB pictures on its radon kits page lists the contents as instructions, two short-term detectors and a pre-paid return mailer, and carries the number RA400; PRO-LAB's store page describes the kit as two tests at the same time and location. PRO-LAB's FAQ refers to the information form that goes back with the sample, and its published instructions to a test location form.

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's store page says the RA400 gives a professional radon analysis using patented liquid scintillation technology. The detectors are passive: nothing in them runs on power or shows a number, and the measurement is made at the laboratory after they come back. PRO-LAB's FAQ describes the routine for its short-term kit: take the caps off when you place the canisters, put them back when the exposure time is over, return the canisters for analysis, and do not remove what is inside. On its short-term kit page PRO-LAB adds that its liquid scintillation detectors contain a patented silica gel desiccant to remove moisture. The EPA names charcoal liquid scintillation devices among the detectors most commonly used for short-term testing, and describes passive devices as needing no power, exposed to the air in the home for a set time and then sent to a laboratory for analysis.

The kit holds two detectors. PRO-LAB's store page says it lets you take two tests at the same time and location in order to get precise results, and the guidance on PRO-LAB's short-term kit page works from the average of the two results, compared with 4.0 pCi/L. The EPA describes the same arrangement as one of its options for a home sale, two short-term tests at the same time in the same location for at least 48 hours, and says two simultaneous tests improve the precision of the measurement, while one test followed by another would more likely represent the seasonal average.

The RA400's store page gives no exposure time. PRO-LAB's FAQ says its short-term radon gas kit is designed for an exposure time of 48 to 96 hours and can be a single or double canister kit. The instructions PRO-LAB publishes on its short-term kit page give the same window for its two detectors: leave them uncapped and undisturbed in the same place for at least 48 hours and no more than 96, and the results are invalid if they stay open for less or more, so you would need another kit to repeat the test.

PRO-LAB's own pages leave one gap. The FAQ's answer on minimum and maximum exposure times goes model by model and does not list the RA400: it gives the RA100 a minimum of 48 hours and a maximum of 168 hours, seven full days, and the RA148 48 to 120 hours, and says a sample exposed for less than 48 hours gets a report without a radon level, marked underexposed. This page uses 48 to 96 hours, the figure PRO-LAB gives for its short-term kit as a whole. If the instructions printed in your RA400 box give a different window, follow them, or ask PRO-LAB before you start.

The EPA counts any test from two to 90 days as short-term and says radon tests should run for a minimum of 48 hours. Because radon levels vary from day to day and season to season, it says a long-term test, more than 90 days, is more likely to tell you a home's year-round average. Averaging two detectors does not change that: the EPA's guide for home buyers and sellers notes that if the average of two short-term tests is 4.1 pCi/L, there is about a 50 percent chance that the year-round average is somewhat below, or above, 4 pCi/L.

What to do with the result follows the EPA's steps rather than the kit's. After a first short-term result at or above 4 pCi/L, the EPA says to take a follow-up test, either a long-term test or a second short-term test, and it suggests considering a fix between 2 and 4 pCi/L.

What the manufacturer says

PRO-LAB's own statements, attributed

  • PRO-LAB saysPRO-LAB lists the RA400 as its short-term radon gas test kit with lab analysis included, UPC 683431994003.
  • PRO-LAB saysPRO-LAB states that laboratory results come within 7 days, and that an express service is available for an additional fee.
  • PRO-LAB saysPRO-LAB states that the kit uses patented liquid scintillation technology and lets you take two tests at the same time and location to get precise results.
  • PRO-LAB saysPRO-LAB describes the RA400 as valid for real estate transactions; check your state's rules for sale tests before relying on it.
  • PRO-LAB saysPRO-LAB states that registering a 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 is not owned by or beholden to any company selling pollution abatement services or air or water treatment devices.

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 RA400. 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 names liquid scintillation for the RA400 but not the vial, so this records the laboratory, not a confirmed device for this kit. Checked October 8, 2026.

Specifications

Specifications

Every figure as the maker states it

Compare side by side

The maker's figures

Type
Short-term test kit, two liquid scintillation detectors, mail-in, lab fee included
How it measures
Liquid scintillation, two detectors side by side, laboratory analysis
Exposure time
48 hours to 96 hours
Lab fee
Included in the kit
Power
None needed
Units
pCi/L

What is in the box

The RA400 box PRO-LAB pictures on its radon kits page lists the contents as instructions, two short-term detectors and a pre-paid return mailer, and carries the number RA400; PRO-LAB's store page describes the kit as two tests at the same time and location. PRO-LAB's FAQ refers to the information form that goes back with the sample, and its published instructions to a test location form.

PRO-LAB's FAQ says it does not send replacements for lost or misplaced prepaid mailers; if yours goes missing, you can send the kit to the address on the information form or to PRO-LAB's physical address. Registering the kit is optional, and reports are emailed or mailed either way. Neither the store page nor the FAQ states a warranty for the kit.

What it costs to run

The standard analysis is paid for with the kit: PRO-LAB lists the RA400 as its short-term kit with lab analysis included, and its store page gives results within 7 days. The RA400 box PRO-LAB pictures lists a pre-paid return mailer. There is nothing to power and no subscription.

Two things cost extra. PRO-LAB's store page says express service is available for an additional fee, and PRO-LAB's short-term instructions say express samples must travel by an overnight carrier, a shipping cost of its own. New Jersey adds a fee: PRO-LAB's FAQ says 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. The two RA400 box pictures on PRO-LAB's sites print different amounts for it, so confirm the current figure with PRO-LAB.

PRO-LAB also sells its short-term kit without the analysis; on that kit's page the lab fee goes back with the detectors. If your result is at or above 4 pCi/L, the EPA's next step is a follow-up test, a second short-term kit or a long-term one, so plan for a second purchase in that case.

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 the standard laboratory fee paid with the kit rather than sent back with the detectors.
  • You want two detectors side by side, so the result is the average of two simultaneous measurements.
  • You can keep the house closed for two to four days and the 12 hours before the test starts.
  • You can mail the detectors back within a day of capping them.
  • You want to know when the lab has your sample and to see the report by email or online.

Look elsewhere if

  • You want to follow radon over weeks or months; this is a two-to-four-day measurement.
  • Your home sale needs a test by a licensed or certified professional under your state's rules.
  • You may not be home to cap the detectors within 96 hours of opening them.
  • You want fast results without paying extra for express analysis and overnight shipping.
  • You want a reading on a screen rather than a mailed laboratory report.

Setup and placement

4 steps

  1. PRO-LAB's published short-term instructions sit on its short-term kit page, the kit sold without the analysis; this page follows them for the RA400, minus the payment step. Where the instructions in your box differ, follow the box. Start with closed-house conditions. PRO-LAB's FAQ defines them as every door and window in the home, attic and basement windows included, closed for 12 hours before the test starts and throughout it, with exterior doors used only for normal entry and exit. The short-term instructions PRO-LAB publishes add the rest: do not run fans, whole house fans or fireplaces; keep an installed radon mitigation system running; run the furnace and central heating or air conditioning normally; run a window air conditioner with its vent closed or in recycle mode; and do not test during severe weather.
  2. Placement, in PRO-LAB's terms: the lowest livable level, which its FAQ defines 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. The instructions say to keep the detectors away from drafts, vents, doors and windows, and out of the kitchen, laundry room and closets, direct sunlight and any heat source. Remove and keep the caps, set the two 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 write down the start date and the exact time in hours and minutes.
  3. To end the test, put the caps back on both detectors and record the end date and time. PRO-LAB's instructions ask for the detectors to go into the prepaid envelope within 24 hours of the end of the test, with the completed test location form. Express samples, the instructions add, go by an overnight carrier such as FedEx or UPS and can only be received Monday to Friday, and PRO-LAB's FAQ says anything sent by express or overnight shipping goes to its 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, in 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 clears the EPA's 20 inches. For a short-term test of two to four days, the EPA says closed-house conditions should hold for at least 12 hours before the test and for the whole of it, not to run a test lasting less than four days during severe storms or high winds, not to disturb the device, and to return it to the laboratory promptly with the start and stop times and test location recorded.

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

Compare

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The same three rows for each, and the one difference that matters

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Questions

Questions people ask

6 questions about the PRO-LAB RA400, answered

Asked about the RA400

Is the lab fee really included?

The standard analysis is. PRO-LAB's radon kits page lists the RA400 as its short-term kit with lab analysis included, and its store page gives laboratory results within 7 days. Express service costs an additional fee, and New Jersey residents pay a state administrative fee on top, which PRO-LAB's FAQ says goes to the New Jersey Department of Environmental Protection.

How long do I leave the RA400 detectors out?

PRO-LAB's FAQ says its short-term kit is designed for 48 to 96 hours, and the short-term instructions PRO-LAB publishes say at least 48 hours and no more than 96, with results invalid outside that window. Write down the start and end dates and times to the minute.

The RA400's store page gives no exposure time, and the FAQ's model-by-model answer on exposure lists the RA100 and the RA148 but not the RA400. Follow the instructions printed in your box if they differ, or call PRO-LAB first.

Can I use the RA400 for a home sale?

PRO-LAB describes it as valid for real estate transactions. That is PRO-LAB's statement, and whether a do-it-yourself kit is accepted for a sale depends on your state and on the buyer and seller. Many states require radon professionals to be licensed, certified or registered, so check your state's rules for sale tests before relying on any do-it-yourself kit.

The EPA's guide for buyers and sellers lists three short-term options for a sale, among them two tests at the same time in the same place, which is what this kit's two detectors do, and says any real estate test should include steps to prevent or detect interference with the test device.

How is the RA400 different from PRO-LAB's RA100?

PRO-LAB lists them as separate kits. The RA400 includes the standard analysis; with the kit sold on PRO-LAB's short-term kit page, the lab fee goes back with the detectors, and its instructions list a standard and an express fee. PRO-LAB's FAQ also gives the RA100 its own exposure range, 48 to 168 hours, which it does not give the RA400.

Who analyzes the detectors, and is the laboratory accredited?

PRO-LAB says all analyses are performed by PRO-LAB or by laboratories it recognizes as licensed, certified or accredited. Overnight and express samples go to Professional Laboratories at its Weston, Florida street address, its FAQ says.

The National Radon Safety Board, which accredits laboratories to analyze specific approved devices, lists Pro-Lab Inc of Weston, Florida as ARL0028 in its June 2026 list, with an accreditation expiry of March 30, 2027. The devices listed for that laboratory are a Beckman Ready Rad liquid scintillation vial, NRSB device 12191, and a Pro Lab alpha track detector. PRO-LAB names liquid scintillation for the RA400 but not the vial, so the listing confirms the laboratory, not which device is in this kit.

How will I know the lab has my sample, and how do results arrive?

PRO-LAB's FAQ says that if you put an email address on the information form or registration, a confirmation email reports the sample's arrival and the turnaround you asked for. You can also check with your registration number online, call, or email PRO-LAB with your name, address, test type and the radon serial numbers.

The store page gives standard results within 7 days, as does the FAQ. For express, the FAQ says 2 days and the short-term instructions say 3 business days. Add mailing time to any of these figures.

What to do next

Updated October 8, 2026