Troubleshooting Poor Spike-Recovery Results

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-27

Quick Answer

Poor spike recovery usually traces to extraction inefficiency, matrix interference, or analyte instability, so verify each step with matrix-matched controls before changing the assay.
Run a parallel unspiked sample and a spike into buffer to distinguish recovery loss from background effects, then adjust the workflow based on that comparison.
Recovery outside the expected range does not automatically invalidate an assay, but it does require documented investigation and a stated interpretation limit.

Understanding Spike Recovery in Analytical Workflows

Spike recovery is a core diagnostic check in laboratory method validation and routine quality control. The procedure involves adding a known quantity of analyte to a sample matrix, processing the sample through the complete workflow, and then measuring how much of the added analyte is detected at the end. The ratio of measured to expected concentration, expressed as a percentage, is the recovery value. A recovery near 100 percent indicates that the method detects the analyte accurately in that matrix. Low recovery suggests analyte loss during processing or suppression of the signal. High recovery suggests contamination, matrix enhancement, or a calibration error.

The purpose of this article is to give laboratory professionals a systematic path for diagnosing poor spike recovery. The content is organized around root causes, corrective actions, and documentation practices. It is written for biology students, researchers, laboratory professionals, and life science practitioners who need to identify why recovery is outside the acceptable range and what to do about it. The guidance follows the evidence mode of academic writing, meaning that claims are tied to authoritative sources in molecular biology, biosafety, measurement science, and reporting standards.

Spike recovery is not a single universal test. It is a family of procedures that vary by analyte, matrix, extraction method, and detection platform. A recovery experiment for a protein in serum differs from one for a nucleic acid in plant tissue. A recovery experiment for a small molecule in urine differs from one for a virus in wastewater. The common thread is the logic of the test. You add a known amount, process the sample, measure the result, and compare the measured value to the expected value. The difference between the two is the recovery loss or gain.

The value of spike recovery lies in its ability to expose problems that are invisible in a standard calibration curve. A calibration curve tells you how the instrument responds to known standards in a clean matrix. It does not tell you how the instrument responds to the same analyte in a complex biological sample. Spike recovery bridges that gap. It tests the entire workflow from sample preparation to detection, beyond the instrument response.

Recovery problems are common in laboratories that work with complex matrices. Blood, serum, plasma, urine, tissue homogenates, plant extracts, soil, and food all contain components that can interfere with extraction and detection. Proteins can bind the analyte and prevent it from being extracted. Lipids can interfere with chromatographic separation. Salts and other matrix components can suppress ionization in mass spectrometry. Enzymes can degrade the analyte during processing. Each of these mechanisms produces a characteristic recovery pattern that can be identified with the right controls.

The diagnostic approach in this article follows a decision tree logic. Start with the simplest explanation and rule it out before moving to more complex ones. Check the spike solution itself. Check the extraction efficiency. Check the matrix effects. Check the detection system. Check the calculations. Each step has a specific control that isolates the variable. The goal is to identify the root cause with the fewest experiments and the least ambiguity.

Core Principles of Recovery Testing

The Recovery Equation

The recovery percentage is calculated by dividing the measured concentration of the spiked sample by the expected concentration and multiplying by 100. The expected concentration is the sum of the endogenous analyte in the sample and the added spike. In practice, the endogenous concentration is measured in a parallel unspiked sample. The recovery equation is then the measured spiked concentration minus the measured unspiked concentration, divided by the added spike concentration, multiplied by 100.

This subtraction step is important. If the sample already contains the analyte, the measured spiked value includes both the endogenous and the added analyte. Failing to subtract the endogenous value inflates the recovery. The result looks acceptable when the extraction is actually failing. The unspiked sample is therefore not optional. It is a required control for any recovery calculation in a matrix that may contain the analyte.

The spike concentration should be chosen to fall within the linear range of the assay. If the spike pushes the total concentration above the linear range, the measured value will be lower than expected and the recovery will appear low even though the assay is working correctly. If the spike is too low, the measurement may be dominated by noise or by the endogenous signal. The spike level should be comparable to the expected concentration of the analyte in the samples being tested.

The Role of the Matrix

The matrix is everything in the sample except the analyte. It includes proteins, lipids, salts, carbohydrates, nucleic acids, and small molecules. The matrix can affect recovery in several ways. It can bind the analyte and prevent it from being extracted. It can degrade the analyte through enzymatic activity. It can interfere with the detection step by suppressing or enhancing the signal. It can also change the physical properties of the sample, such as viscosity or pH, which affects how the sample flows through the extraction and analysis system.

Matrix effects are not constant across samples. Two samples of the same type can have different matrix compositions. A blood sample from a healthy donor differs from a blood sample from a patient with a metabolic disease. A soil sample from one field differs from a soil sample from another field. This variability means that a recovery test on one sample does not guarantee the same recovery on another sample. Recovery testing should be repeated across representative samples of the matrix type.

The matrix can also change over time. A stored sample may develop precipitates or microbial growth. A frozen sample may lose volatile analytes. A sample that has been through multiple freeze thaw cycles may have degraded proteins. These changes affect recovery and should be documented in the sample handling records.

The Difference Between Recovery and Sensitivity

Recovery is a measure of the yield of the entire analytical process. Sensitivity is a measure of the smallest amount of analyte that can be detected. The two are related but distinct. A method can have high sensitivity and low recovery. The instrument can detect a tiny amount of analyte, but the extraction loses most of the analyte before it reaches the instrument. A method can also have high recovery and low sensitivity. The extraction is efficient, but the instrument cannot detect small amounts of the analyte.

The distinction matters for troubleshooting. If recovery is low, the problem is likely in the extraction or the matrix. If sensitivity is low, the problem is likely in the detection system. The two problems require different fixes. A recovery problem is fixed by changing the extraction or the matrix handling. A sensitivity problem is fixed by changing the detection parameters or the instrument.

The Role of Controls

Controls are the backbone of spike recovery troubleshooting. A well designed recovery experiment includes several controls that isolate the source of the problem. The unspiked sample measures the endogenous analyte. The spike into buffer measures the performance of the extraction and detection in a clean matrix. The spike into the sample measures the performance in the real matrix. The difference between the buffer spike and the sample spike is the matrix effect.

The buffer spike is often overlooked. It is a simple control that answers a basic question: does the assay work at all? If the buffer spike recovers poorly, the problem is in the extraction or the detection, not the matrix. If the buffer spike recovers well but the sample spike does not, the problem is in the matrix. This single comparison divides the troubleshooting space in half.

Additional controls can be added to isolate specific steps. A spike before extraction tests the entire pipeline. A spike after extraction tests only the detection step. A spike into the final extract tests the matrix effect on the detection without the extraction step. The combination of these spikes can pinpoint the exact step where the analyte is lost.

At a Glance

Symptom	Likely Cause	First Check	Corrective Action
Low recovery in sample but normal in buffer	Matrix interference	Compare buffer spike to sample spike	Dilute the sample, add a matrix modifier, or change the extraction
Low recovery in both buffer and sample	Extraction or detection failure	Spike after extraction	Check the extraction protocol and the detector settings
High recovery in sample	Contamination or matrix enhancement	Run a blank and an unspiked sample	Identify the contamination source or correct the matrix effect
Variable recovery across replicates	Inconsistent sample handling	Check the extraction steps	Standardize the sample preparation and the extraction
Recovery changes with storage	Analyte instability	Test fresh and stored samples	Change the storage conditions or the stabilizer

Practical Workflow for Diagnosing Poor Recovery

Step 1: Verify the Spike Solution

The first step is to confirm that the spike solution itself is correct. The spike solution is the stock solution of the analyte that is added to the sample. If the spike solution is degraded, the wrong concentration, or contaminated, the recovery result will be wrong regardless of the rest of the assay.

Check the preparation date and the storage conditions of the spike solution. Many analytes degrade over time, especially when stored in solution. Proteins can aggregate or precipitate. Nucleic acids can be degraded by nucleases. Small molecules can oxidize or hydrolyze. The stability of the spike solution should be documented in the laboratory records.

Check the concentration of the spike solution. The concentration is calculated from the mass of the analyte and the volume of the solvent. An error in either value changes the spike concentration. The concentration should be verified with an independent measurement, such as a spectrophotometer reading or a standard curve.

Check the solvent of the spike solution. The solvent must be compatible with the sample matrix. If the solvent is not miscible with the sample, the spike will not mix evenly. If the solvent changes the pH of the sample, the analyte may degrade or bind to the matrix. The solvent should be the same as the sample buffer or a solvent that is known to be compatible.

Step 2: Run the Buffer Spike

The buffer spike is the control that tests the assay in a clean system. Prepare a sample of the buffer that is used in the assay, spike it with the same amount of analyte, and process it through the entire workflow. The buffer should be the same buffer that is used in the sample preparation, not a generic buffer. The buffer spike should recover near 100 percent if the assay is working.

If the buffer spike recovers poorly, the problem is in the assay itself. The extraction may be inefficient. The detection may be suppressed. The analyte may be binding to the extraction materials. The problem is not the matrix because the matrix is absent.

If the buffer spike recovers well, the problem is in the matrix. The matrix is interfering with the extraction or the detection. The next step is to identify the specific matrix component that is causing the problem.

Step 3: Run the Sample Spike

The sample spike is the actual recovery test. Spike the sample with the same amount of the analyte and process it through the assay. The recovery is calculated by subtracting the endogenous analyte and dividing by the added spike.

The sample spike should be run in parallel with the unspiked sample. The unspiked sample measures the endogenous analyte. The difference between the spiked and unspiked samples is the recovered spike. The two samples should be processed identically, at the same time, and by the same person.

The sample spike should be run in replicate. A single measurement is not enough to distinguish a recovery problem from a random error. The replicates should be at least three, and the variability between them should be documented. The recovery is reported as the mean and the standard deviation.

Step 4: Compare the Buffer and Sample Spikes

The comparison between the buffer spike and the sample spike is the key diagnostic. If the buffer spike recovers well and the sample spike does not, the matrix is the cause. If both recover poorly, the assay is the cause.

The comparison is not always clean. The buffer spike may recover at 80 percent and the sample spike at 60 percent. The difference is the matrix effect. The matrix effect is the reduction in recovery caused by the sample matrix. The matrix effect can be quantified as the difference between the two recoveries.

The matrix effect can be reduced by diluting the sample. Dilution reduces the concentration of the matrix components. The analyte concentration is also reduced, so the dilution must be balanced against the sensitivity of the assay. The matrix effect can also be reduced by adding a matrix modifier, such as a protein stabilizer or a chelating agent.

Step 5: Spike After Extraction

The spike after extraction is a control that isolates the detection step. The sample is processed through the extraction, and the spike is added to the extract. The extract is then measured. The recovery of this spike tests the detection without the extraction.

If the spike after extraction recovers well, the extraction is the problem. The analyte is being lost during the extraction. The extraction method needs to be changed. If the spike after extraction recovers poorly, the detection is the problem. The detection system is not measuring the analyte correctly.

The spike after extraction is a simple control that is often omitted. It is a valuable addition to the troubleshooting workflow because it separates the extraction from the detection.

Step 6: Check the Detection System

The detection system is the instrument or the assay that measures the analyte. The detection system can be a spectrophotometer, a chromatograph, a mass spectrometer, a plate reader, or a gel imager. The detection system can have its own problems that affect the recovery.

Check the calibration of the detection system. The calibration curve should be run on the same day as the recovery test. The calibration curve should cover the range of the expected concentrations. The calibration curve should be linear in the range of the spike.

Check the detection parameters. The wavelength, the gain, the integration time, and the other parameters should be optimized for the analyte. The parameters should be the same for the calibration and the recovery test.

Check the detection for contamination. The detector can be contaminated by a previous sample. The contamination can cause a high background or a false signal. The detector should be cleaned and the background should be checked.

Common Failure Patterns

Low Recovery in the Buffer Spike

Low recovery in the buffer spike indicates a problem in the assay itself. The extraction is losing the analyte, or the detection is not measuring it. The buffer is a clean system, so the matrix is not the cause.

The extraction can lose the analyte in several ways. The analyte can bind to the extraction column or the extraction resin. The analyte can be washed off during the washing step. The analyte can be degraded by the extraction reagents. The analyte can be lost during the evaporation or the reconstitution step.

The detection can fail to measure the analyte for several reasons. The detection can be suppressed by the buffer components. The detection can be out of the linear range. The detection can be miscalibrated. The detection can be contaminated.

The corrective action is to check the extraction and the detection separately. The spike after the extraction tests the detection. The spike before the extraction tests the extraction. The comparison between the two identifies the failing step.

Low Recovery in the Sample

Low recovery in the sample with normal recovery in the buffer indicates a matrix effect. The matrix is interfering with the analyte. The matrix can bind the analyte, degrade the analyte, or suppress the detection.

The matrix binding is a common cause. The analyte can bind to the proteins, lipids, or other components of the matrix. The bound analyte is not extracted. The recovery is low because the analyte is not available for the extraction.

The matrix degradation is another cause. The matrix can contain enzymes that degrade the analyte. The degradation can occur during the sample preparation or during the extraction. The recovery is low because the analyte is destroyed.

The matrix suppression is a third cause. The matrix can suppress the detection. The suppression is common in mass spectrometry, where the matrix components can interfere with the ionization. The recovery is low because the signal is reduced.

The corrective action is to reduce the matrix effect. The sample can be diluted. The matrix can be removed by a cleanup step. The matrix can be modified by adding a stabilizer or a competitor.

High Recovery

High recovery is less common than low recovery, but it is a real problem. High recovery indicates that the measured value is higher than the expected value. The high recovery can be caused by contamination, a matrix effect, or a calculation error.

Contamination is the most common cause. The spike solution can be contaminated with a higher concentration of the analyte. The sample can be contaminated during the preparation. The extraction can be contaminated by a previous sample. The contamination can be detected by running a blank sample.

The matrix effect can also cause high recovery. The matrix can enhance the detection of the analyte. The enhancement is the opposite of the suppression. The matrix can also contain a compound that is measured as the analyte. The compound is a false positive.

The calculation error is a third cause. The spike concentration can be calculated incorrectly. The endogenous concentration can be subtracted incorrectly. The dilution factor can be applied incorrectly. The calculation should be checked and rechecked.

Variable Recovery

Variable recovery is a recovery that changes between replicates or between runs. The variability can be caused by inconsistent sample handling, inconsistent extraction, or inconsistent detection.

The sample handling can be inconsistent. The sample can be mixed differently. The sample can be stored differently. The sample can be processed at different times. The variability can be reduced by standardizing the sample handling.

The extraction can be inconsistent. The extraction can be performed by different people. The extraction can be performed with different batches of reagents. The extraction can be performed at different temperatures. The variability can be reduced by standardizing the extraction.

The detection can be inconsistent. The detection can be performed on different days. The detection can be performed with different instruments. The detection can be performed with different parameters. The variability can be reduced by standardizing the detection.

Decision Tree for Recovery Troubleshooting

The decision tree is a structured way to work through the recovery problem. The tree starts with the most basic question and works toward the specific cause. The tree is a guide, not a rule. The order of the steps can be adjusted based on the specific assay and the specific problem.

flowchart TD
    A[Recovery outside the acceptable range] --> B{Is the buffer spike normal?}
    B -->|Yes| C{Is the sample spike low?}
    C -->|Yes| D[Matrix effect suspected]
    D --> E{Does dilution fix the recovery?}
    E -->|Yes| F[Use diluted sample or add a matrix modifier]
    E -->|No| G{Does a cleanup step fix the recovery?}
    G -->|Yes| H[Add a cleanup step to the extraction]
    G -->|No| I[Check for analyte binding or degradation in the matrix]
    B -->|No| J{Does the spike after extraction recover?}
    J -->|Yes| K[Extraction is the problem]
    K --> L[Check the extraction and the extraction reagents]
    J -->|No| M[Detection is the problem]
    M --> N[Check the detection and the calibration]

The decision tree starts with the buffer spike. The buffer spike is the first control because it separates the assay from the matrix. If the buffer spike is normal, the assay is working and the problem is in the matrix. If the buffer spike is low, the assay is not working and the problem is in the extraction or the detection.

The next branch is the spike after the extraction. The spike after the extraction separates the extraction from the detection. If the spike after the extraction recovers, the extraction is the problem. If the spike after the extraction does not recover, the detection is the problem.

The decision tree is a simplification. The real troubleshooting may require multiple experiments and multiple controls. The decision tree is a starting point that organizes the process.

Records and Measurements

What to Record

The recovery experiment should be documented in the laboratory records. The documentation should include the date, the analyst, the sample type, the sample identification, the spike concentration, the spike volume, the buffer type, the extraction method, the detection method, the measured values, and the calculated recovery.

The documentation should also include the controls. The buffer spike, the unspiked sample, and the spike after the extraction should be recorded. The controls are as important as the recovery value itself. The controls are the evidence that the recovery value is valid.

The documentation should include the calculations. The recovery calculation should be shown in the records. The calculation should include the subtraction of the endogenous concentration and the dilution factor. The calculation should be checked by a second person.

The documentation should include the observations. The observations include the appearance of the sample, the behavior of the extraction, and the performance of the detection. The observations can be useful for diagnosing the problem.

How to Measure

The recovery is measured by the assay. The assay can be a chromatographic, a spectrometric, a PCR, or an immunoassay. The assay should be calibrated on the same day as the recovery test. The calibration should be run in the same matrix as the recovery test.

The recovery should be measured in replicate. The replicates should be at least three. The replicates should be processed in the same batch. The replicates should be measured in the same run. The recovery is the mean of the replicates.

The recovery should be measured with the same instrument and the same parameters as the calibration. The instrument should be in the same condition. The instrument should be cleaned and checked before the recovery test.

How to Interpret the Results

The recovery is interpreted by comparing it to the acceptable range. The acceptable range is defined by the laboratory or the method. The acceptable range is typically 80 to 120 percent for many assays, but the range can be different for different methods. The acceptable range should be documented in the method.

The recovery is not a single value. The recovery is a distribution. The recovery should be reported as the mean and the standard deviation. The standard deviation is a measure of the variability of the recovery.

The recovery should be interpreted in the context of the controls. The recovery is valid only if the controls are valid. The buffer spike should be normal. The unspiked sample should be consistent. The spike after the extraction should be normal.

Common Failure Patterns

Failure Pattern 1: The Buffer Spike Is Low

The buffer spike is low, and the sample spike is also low. The problem is in the assay. The extraction or the detection is failing. The buffer is a clean system, so the matrix is not the cause.

The most common cause is the extraction. The extraction is not efficient. The analyte is lost during the extraction. The extraction method needs to be changed. The extraction reagents need to be checked. The extraction time and temperature need to be optimized.

The second most common cause is the detection. The detection is not measuring the analyte correctly. The detection is suppressed or miscalibrated. The detection parameters need to be checked. The calibration needs to be verified.

The corrective action is to run the spike after the extraction. The spike after the extraction isolates the extraction from the detection. If the spike after the extraction recovers, the extraction is the problem. If the spike after the extraction does not recover, the detection is the problem.

Failure Pattern 2: The Buffer Spike Is Normal and the Sample Spike Is Low

The buffer spike is normal, and the sample spike is low. The pattern is a matrix effect. The matrix is interfering with the analyte. The matrix is binding the analyte, degrading the analyte, or suppressing the detection.

The most common cause is the matrix binding. The analyte is binding to the matrix components. The bound analyte is not extracted. The recovery is low.

The second most common cause is the matrix suppression. The matrix is suppressing the detection. The suppression is common in mass spectrometry. The recovery is low because the signal is reduced.

The corrective action is to reduce the matrix effect. The sample can be diluted. The matrix can be removed by a cleanup step. The matrix can be modified by a stabilizer.

Failure Pattern 3: The Recovery Is High

The recovery is high, and the controls are normal. The pattern is contamination or a matrix effect. The measured value is higher than the expected value.

The most common cause is contamination. The spike solution is contaminated. The sample is contaminated. The extraction is contaminated. The contamination can be detected by running a blank.

The second most common cause is a matrix effect. The matrix is enhancing the detection. The matrix is adding a compound that is measured as the analyte. The matrix effect can be detected by running a matrix blank.

The corrective action is to check the contamination and the matrix. The blank should be run. The matrix blank should be run. The spike solution should be checked.

Failure Pattern 4: The Recovery Is Variable

The recovery is variable. The replicates are different. The recovery is not reproducible. The variability is caused by inconsistent sample handling, inconsistent extraction, or inconsistent detection.

The most common cause is the sample handling. The sample is not mixed consistently. The sample is not stored consistently. The sample is not processed consistently.

The second most common cause is the extraction. The extraction is not consistent. The extraction is performed by different people. The extraction is performed with different reagents.

The corrective action is to standardize the process. The sample handling is standardized. The extraction is standardized. The detection is standardized. The standard operating procedure is written and followed.

Quality Controls and Standards

The Role of Quality Controls

Quality controls are the samples that are used to verify the performance of the assay. The quality controls are run with the recovery test. The quality controls are the buffer spike, the unspiked sample, and the spike after the extraction.

The quality controls are the basis of the recovery interpretation. The recovery is valid only if the controls are valid. The controls are the evidence that the assay is working.

The quality controls should be run in every recovery test. The controls should be run in the same batch as the recovery. The controls should be run with the same reagents and the same method.

The Role of Standards

Standards are the reference materials that are used to calibrate the assay. The standards are the known concentrations of the analyte. The standards are used to create the calibration curve.

The standards should be traceable to a reference. The reference can be a certified reference material or a standard from a recognized source. The traceability is the basis of the measurement. The traceability is documented in the laboratory records.

The standards should be checked for stability. The standards can degrade over time. The standards should be stored in the correct conditions. The standards should be checked for the concentration.

The Role of Biosafety

The spike recovery experiment can involve biological samples. The biological samples can contain infectious agents. The samples should be handled according to the biosafety guidelines. The biosafety guidelines are described in the Biosafety in Microbiological and Biomedical Laboratories manual from the CDC and NIH.

The biosafety level is determined by the risk of the sample. The risk is assessed by the laboratory. The risk assessment is documented. The containment is based on the risk assessment.

The biosafety is a part of the laboratory quality. The biosafety is not separate from the quality. The biosafety is the basis of the safe operation of the laboratory.

Limitations and Escalation Criteria

Limitations of the Recovery Test

The recovery test is a diagnostic tool, but it has limitations. The recovery test does not identify the exact cause of the problem. The recovery test identifies the step of the assay that is failing. The exact cause requires further investigation.

The recovery test is not a measure of the accuracy of the assay. The recovery is a measure of the yield of the assay. The accuracy is the closeness of the measured value to the true value. The recovery is one component of the accuracy.

The recovery test is not a measure of the precision of the assay. The recovery is a measure of the yield. The precision is the closeness of the replicates. The recovery test can be precise and inaccurate. The recovery test can be accurate and imprecise.

When to Escalate

The recovery problem should be escalated when the corrective actions do not fix the problem. The escalation is the process of involving a more experienced person or a specialist. The escalation is a professional decision.

The escalation is appropriate when the recovery is consistently low or high. The escalation is appropriate when the recovery is variable. The escalation is appropriate when the recovery problem is not understood.

The escalation is appropriate when the problem is a safety issue. The safety issue is a risk to the laboratory or the environment. The safety issue is a risk to the analyst. The safety issue is a risk to the public.

The escalation is appropriate when the problem is a regulatory issue. The regulatory issue is a requirement of the method or the laboratory. The regulatory issue is a requirement of the accreditation. The regulatory issue is a requirement of the law.

Frequently Asked Questions

What is the acceptable range for spike recovery?

The acceptable range is defined by the method or the laboratory. A common range is 80 to 120 percent, but the range can vary by the method and the matrix. The acceptable range should be documented in the method and verified with the controls.

Why is my recovery low in the sample but normal in the buffer?

The low recovery in the sample with a normal buffer spike indicates a matrix effect. The matrix is interfering with the analyte. The matrix can bind the analyte, degrade the analyte, or suppress the detection. The corrective action is to reduce the matrix effect by dilution, cleanup, or a matrix modifier.

Why is my recovery high?

The high recovery is caused by contamination, a matrix effect, or a calculation error. The contamination is detected by a blank. The matrix effect is detected by a matrix blank. The calculation error is detected by checking the calculation.

How many replicates should I run for a spike recovery test?

The number of replicates depends on the method and the variability. A minimum of three replicates is common. The replicates should be processed independently and measured in the same run. The recovery is reported as the mean and the standard deviation.

What is the difference between a spike before extraction and a spike after extraction?

The spike before the extraction tests the entire pipeline. The spike after the extraction tests the detection only. The difference between the two isolates the extraction step. The spike before the extraction is the recovery test. The spike after the extraction is the control.

Can I use the recovery test to validate a new method?

The recovery test is one component of the method validation. The recovery test measures the yield of the method. The method validation also includes the precision, the accuracy, the sensitivity, and the specificity. The recovery test is not the only validation.

What should I do if the recovery is low and the controls are normal?

If the recovery is low and the controls are normal, the problem is in the matrix. The matrix is interfering with the analyte. The corrective action is to reduce the matrix effect. The sample can be diluted. The matrix can be removed by a cleanup step. The matrix can be modified by a stabilizer.

How do I document the spike recovery results?

The documentation should include the date, the analyst, the sample type, the spike concentration, the measured values, and the calculated recovery. The documentation should include the controls. The documentation should include the observations. The documentation should be checked by a second person.

Using the Evidence

Source	Best use in this topic	Important limitation
Molecular Biology and Laboratory Methods	official guidance	Check the linked page for current local requirements
Biosafety in Microbiological and Biomedical Laboratories	official guidance	Check the linked page for current local requirements
NIH Guidelines for Recombinant or Synthetic Nucleic Acid Molecules	official guidance	Check the linked page for current local requirements

Related Diagnostic Guides

References and Further Reading

Molecular Biology and Laboratory Methods. National Library of Medicine.
Biosafety in Microbiological and Biomedical Laboratories. CDC and NIH.
NIH Guidelines for Recombinant or Synthetic Nucleic Acid Molecules. National Institutes of Health.
Addgene Protocols. Addgene.
MIQE Guidelines. Clinical Chemistry.
NIST Laboratory Programs. National Institute of Standards and Technology.
Laboratory Biosafety Manual. World Health Organization.
NCBI Literature Resources. National Center for Biotechnology Information.
Protocol for total RNA sequencing analysis of extracellular RNA from biofluids.. 2026.
Protocol for the recovery and deep sequencing of short ssDNA pools from transient, fuel-dependent coacervate droplets.. 2026.
Limited value of Nanopore adaptive sampling in a long-read metagenomic profiling workflow of clinical sputum samples.. 2025.

This article is educational and does not replace validated laboratory procedures, institutional biosafety review, manufacturer instructions, or professional interpretation.