Swab and Rinse Recovery Study Calculator (Spiked Levels, Mean Recovery, RSD)
Recovery by level and surface, the RSD and the factor to correct routine results with.
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Recovery study
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About the Swab and Rinse Recovery Study Calculator (Spiked Levels, Mean Recovery, RSD)
Evaluates a swab or rinse recovery study for cleaning validation. Paste one result a line, the surface, the spike level, the amount spiked and the amount recovered (from a spreadsheet if you keep them there), and the calculator gives each result's recovery, each level's mean, standard deviation and RSD, each surface's overall recovery and the correction factor to apply to its routine results, with the worst case across surfaces.
Each spike level is checked against your protocol's minimum recovery and RSD limit and against APIC's floor of 50 %, the design against APIC's 9 results over 3 levels, the spike levels against the LOQ, and the correction follows APIC: 90 % or more need not be taken into account, below 90 % the result is divided by the recovery. The report follows the method you choose; your QA approves the result.
Without a pass the free preview runs the whole evaluation and shows the verdict of every level, the checks, the limits that apply and the method; the recoveries, RSDs, correction factors and the PDF, Word and Excel files and the printout unlock with an Ultimate pass.
How to use it
- Name the residue and choose swab or rinse sampling and the unit of the amounts.
- Paste the results one a line: surface; spike level (for example 50 %, 100 %, 150 % or LOQ); amount spiked; amount recovered.
- Enter your protocol’s minimum recovery (for example 70 %) and RSD limit (for example 15 %), and the LOQ to check the lowest level.
- Choose the recovery that corrects routine results: each surface’s lowest level mean (the worst case) or its overall mean, and whether to correct at 90 % or more.
- Read each surface’s correction factor: a routine result measured on that surface × the factor estimates the residue left on it.
- Save the evaluation as a PDF, a Word file or an Excel workbook, or print it, with an Ultimate pass.
Examples
Stainless steel 316L: 25, 50 and 75 µg spiked, 21.2 / 20.6 / 21.9, 43.1 / 44.0 / 42.2 and 66.0 / 64.5 / 67.2 µg recovered · PTFE gasket the same levels, 15.1 / 14.2 / 16.0, 31.5 / 30.0 / 33.1 and 48.8 / 47.1 / 50.2 µg · minimum 70 %, RSD at most 15 %
Steel: 84.9 %, 86.2 % and 87.9 % by level (RSD 2.1–3.1 %), overall 86.3 %, correction factor 1.177 from the lowest level. PTFE: 60.4 % at the lowest level, below the 70 % minimum: improve the swabbing on PTFE or use its own factor of 1.656 if your protocol allows.
Common uses
- Evaluating the recovery study of a new swab or rinse method before a cleaning validation.
- Working out the correction factor for each product-contact material of an equipment train.
- Checking that the recovery and its precision meet the protocol at every spike level.
- Finding the surface whose sampling needs improving before the study is repeated.
What APIC asks of a recovery study
From APIC's Guidance on aspects of cleaning validation in active pharmaceutical ingredient plants, 8.2.4 and 8.2.5:
- Determination: spike a surface equivalent to the equipment surface (material, polish grade) with different known amounts of the residue, recover it and analyse it with the sampling and analytical methods of the cleaning validation study, and report the recovery as a percentage of the amount applied.
- Use: recoveries of 90 % or more are usually acceptable and need not be taken into account in the result; below 90 % they are included in the calculation of the true residue, M = Mres ÷ R; recoveries below 50 % should be omitted.
- Accuracy: at least 9 determinations over at least 3 concentration levels, for example 3 levels with 3 replicates each.
EU GMP Annex 15, 10.12, adds that the sampling materials and method do not influence the result, and that recovery is shown from all product contact materials sampled in the equipment with all the sampling methods used.
The calculation
- Recovery of a result = 100 × amount recovered ÷ amount spiked.
- Each level: the mean, the sample standard deviation (n − 1) and RSD = 100 × SD ÷ mean.
- Each surface: the mean and RSD of all its results; the recovery used is its lowest level mean or its overall mean.
- Correction factor = 100 ÷ the recovery used (1 at 90 % or more when you follow APIC's allowance). With 50 % recovery the factor is 2: a routine result is doubled, as APIC's example protocol says.
Sources
- APIC (Cefic) publications: Guidance on aspects of cleaning validation in active pharmaceutical ingredient plants, 8.2.4 and 8.2.5
- EU GMP, EudraLex Volume 4: Annex 15, Qualification and validation, 10.12
Limitations
- The minimum recovery and RSD limit are your protocol’s; APIC’s 50 % and 90 % rules are applied as written.
- Spike surfaces of the same material and finish as the equipment; a coupon of another finish gives another recovery.
- Amounts are entered after any blank subtraction; the calculator does not correct for blanks.
- Up to 300 results at a time.
- The report follows the method you choose; your QA approves the result.
- Runs in any current browser on a phone, tablet or computer: the report is worked out as you type, and the PDF, Word and Excel writers load only when you save a file.
Privacy
On this device: nothing is sent
Your results stay in this browser and are never sent anywhere. The PDF, Word and Excel files are made on your device.
Frequently asked questions
What do I get without a pass?
Without a pass, Swab and Rinse Recovery Study Calculator (Spiked Levels, Mean Recovery, RSD) shows the method, the limits that apply and the verdict for your input; computed figures stay hidden until the pass. Until you unlock it, the result can’t be downloaded or printed. An Ultimate pass, a one-time payment unless you choose automatic renewal, unlocks the full result. The pricing page lists the passes and their prices.
What does the Ultimate pass add here?
This tool in full, and every other Pro, Premium and Ultimate tool, for 7 days, 30 days or a year (a pass bought with PayPal leaves out email-address extractors). The pass is a one-time payment unless you choose automatic renewal.
How is swab recovery calculated?
Recovery = 100 × the amount recovered ÷ the amount spiked on the coupon. 42.6 µg recovered from 50 µg spiked is 85.2 %. Each spike level’s replicates give a mean and an RSD, and each surface an overall recovery.
What swab recovery is acceptable?
APIC calls 90 % or more usually acceptable and says it need not be taken into account; below 90 % the recovery is included in the result, and recoveries below 50 % should be omitted: improve the sampling until it recovers more. A protocol may set its own minimum above 50 %, such as 70 %: enter yours and every level is checked against it.
How do I apply the recovery to routine swab results?
Divide the measured residue by the recovery, or multiply it by the correction factor 100 ÷ recovery: with 80 % recovery a result of 4 µg counts as 5 µg. The calculator gives each surface’s factor from its lowest level mean or its overall mean, as you choose.
How many spike levels and replicates are needed?
APIC lists at least 9 determinations over at least 3 levels for accuracy, for example 3 levels in triplicate, levels that bracket the acceptance limit such as 50 %, 100 % and 150 % of it. The calculator warns when a surface has fewer.
Does every surface material need its own recovery?
EU GMP Annex 15, 10.12, asks for recovery to be shown from all product contact materials sampled in the equipment, with all the sampling methods used. The calculator keeps each surface apart and gives the worst case across them.