Complete Fingerstick Procedure Step-by-Step Guide to Capillary Blood Collection

Illustration of capillary blood collection process

for those in search of a dependable method for capillary blood collection, the fingerstick procedure step-by-step guide to capillary blood collection is the ideal resource. this guide carefully walks you through each crucial step, guaranteeing the accurate acquisition of a capillary blood sample with minimal discomfort. prepare to familiarize yourself with the precise steps required for a successful fingerstick blood test.

Key Takeaways

  • Capillary blood collection is a simple, minimally invasive procedure frequently utilized for point-of-care tests, such as glucose monitoring. however, it has limitations for certain types of tests, like coagulation analysis.
  • Factors such as cleanliness of the puncture site, proper hydration levels, and environmental conditions can significantly impact the accuracy of capillary blood collection results.
  • A precise fingerstick procedure involves preparing the lancing device, selecting an appropriate puncture site, cleaning the area, obtaining a sufficient blood volume, and correctly applying the blood sample to the test strip.

Understanding Capillary Blood Collection

Capillary blood collection is a vital procedure that involves pricking the skin to obtain blood from the capillary networks. It’s extensively used for point-of-care testing and management of various medical conditions, promising simplicity and rapid results. This method of obtaining blood is particularly favored for monitoring:

  • glucose levels
  • hemoglobin A1C
  • ketones
  • other tests where only a small volume of blood is required.

The versatility of capillary blood collection is reflected in the diverse methods used to collect the blood. These include pipettes, slides, test strips, or small containers, with common sites for pricking including fingertips, heels, or earlobes. This method is especially advantageous for pediatric patients and those with difficult venous access, as it requires smaller blood volumes for testing.

In neonatal units, capillary blood tests are a critical component, accounting for a majority of procedures during this vulnerable period. Capillary blood collection can also benefit particular populations such as:

  • patients with severe burns
  • obesity
  • older adults
  • those prone to thrombosis
  • individuals self-monitoring glucose levels.

Though the procedure is simple, maintaining standardized protocols for the blood collection procedure, specifically capillary blood sampling, is paramount to ensure the quality and accuracy of test results.

Capillary vs. Venous Blood Collection

Understanding capillary blood collection wouldn’t be complete without comparing it with venous blood draw, another widely used method for blood collection. A venous blood draw is a process performed by clinical staff where blood is drawn from a vein in the arm. This method often provides more precise results as the drawn blood is processed to remove red blood cells. However, bear in mind that differences in analyte concentrations between capillary and venous samples can occur, impacting the precision of test results.

On the other hand, capillary blood sampling, commonly known as a fingerstick, is less invasive and can be performed by individuals without medical training. Despite its simplicity, there are certain limitations. For instance, capillary blood sampling is not suitable for tests such as coagulation analysis or erythrocyte sedimentation rate. Nevertheless, the convenience and simplicity of capillary blood sampling make it a preferred method for many.

Factors Affecting Capillary Blood Collection Accuracy

Although capillary blood collection has many benefits, one must be mindful of the factors that can influence the accuracy of results. Professionals must adhere to standardized procedures to prevent inaccuracies, pain, and tissue damage. The quality of capillary blood samples can be compromised by the small volume of blood collected and variability caused by different puncture sites and techniques.

Additionally, wiping off the first drop of initial blood is crucial as it may contain a small amount of surplus tissue fluid, which could dilute the sample and distort the results. Hydration levels must also be considered; dehydration can lead to imprecise biomarker measurements like cholesterol and kidney functions.

Lastly, environmental factors such as temperature and humidity can significantly affect the accuracy of readings from blood glucose meters and test strips.

Cleanliness of Fingers

One of the key factors influencing the accuracy of capillary blood collection is the cleanliness of fingers. Adequate hand washing helps eliminate residues that may interfere with the blood sample and its results. For instance, dirt or grease on the fingers can lead to inaccurate glucose meter readings. Additionally, neglecting hand washing after handling sweet substances can result in contamination of the test site and potentially yield falsely high blood glucose readings.

Therefore, maintaining a routine of finger cleaning before blood glucose testing is crucial for efficient and accurate diabetes management. The use of warm water and soap or disinfection gels and foams is essential to minimize the risk of infection during capillary blood sampling. After washing, it’s important to allow your fingers to air dry before proceeding with the test.

Obtaining Sufficient Blood Volume

The accuracy of capillary blood collection is significantly influenced by the volume of blood drawn. It is imperative to generate an appropriately sized blood drop, as the blood glucose test strip’s sample area requires complete filling for precise result calculation. This step is pivotal in guaranteeing the accuracy and reliability of the test.

Moreover, it is recommended to discard the first blood drop, as it may contain tissue fluid that could potentially contaminate the bloodstream sample. Applying light pressure to the fingertip is essential to ensure the extraction of a clean and sufficient drop of blood.

Furthermore, the use of a microcollection device with the right blade length and incision depth is crucial. This not only aids in drawing sufficient blood for testing but also minimizes the risk of tissue damage. These considerations play a pivotal role in upholding the accuracy of results obtained through capillary blood collection.

Step-by-Step Guide to Fingerstick Procedure

Illustration of fingerstick procedure step by step guide to capillary blood collection

Now that we have a foundational understanding of capillary blood collection and its influencing factors, let’s delve into a comprehensive guide on the fingerstick procedure. This detailed guide aims to furnish you with the essential knowledge to execute the procedure accurately and safely, ensuring precise results and minimal discomfort.

The procedure encompasses several key steps, beginning with the preparation of the lancing device, followed by the selection of an appropriate testing site, thorough cleaning of the test site, and culminating in the application of the blood sample to the test strip. During the application of the blood sample, it is crucial to exercise caution and avoid wiping or smearing blood on areas outside the designated sample area. This not only safeguards the accuracy of results but also prevents contamination.

This step-by-step guide will meticulously break down each stage of the process, offering detailed instructions to facilitate a successful and reliable procedure.

Preparing the Lancing Device

Initiating the fingerstick procedure involves preparing the lancing device, a handheld tool housing a small, disposable needle known as a lancet, which functions similarly to a tiny, sharp blade. It’s essential to use a new lancet for each test to ensure comfort and minimize the risk of infection. Changing the lancet after every use is crucial to prevent increased pain from a dulled tip and further reduce the risk of infection.

To prepare the lancing device for use, follow the manufacturer’s instructions to insert a new lancet and ensure the device is cocked and ready. This setup ensures a smooth procedure, minimizing potential complications and contributing to a comfortable experience for individuals undergoing the fingerstick procedure.

Selecting the Proper Testing Site

Continuing with the fingerstick procedure, the next step involves carefully selecting the appropriate testing site. For capillary blood collection, the puncture should be made slightly off-center from the fleshy portion of the fingertip, positioned near the side of the fingertip. This strategic placement allows the blood drop to rest on top of the finger, facilitating the efficient filling of the testing device. Opting for the side of the fingertip is not only more comfortable for the patient but also reduces the risk of infection.

In addition to selecting the right testing site, here are some useful tips to enhance the blood testing process:

  • Rotate between fingers: To minimize scarring and the risk of infection, it’s advisable to alternate between fingers and utilize each side of each finger for punctures.
  • Consider the middle or ring finger: For optimum results, the middle or ring finger of the nondominant hand is particularly suitable for blood testing.
  • Avoid puncturing near jewelry: It’s important to refrain from making the puncture where a patient wears a ring, as jewelry may impede blood circulation and potentially affect the collection of the blood sample. This precaution ensures the accuracy and reliability of the testing process.

Cleaning the Test Site

Advancing to the subsequent step in the fingerstick procedure, meticulous attention is directed toward cleaning the test site. This critical phase involves washing hands or the patient’s hands with foam antiseptic hand rub or antiseptic soap and water before the procedure. This precautionary measure serves to avert contamination and guarantee a proper sample. To enhance this process, it’s recommended to opt for non-alcoholic wipes over alcoholic wipes when cleaning the fingers. This choice minimizes the risk of blood dilution by alcohol and helps prevent potential skin irritation or dryness.

Furthermore, refraining from using alcohol wipes before pricking the finger can contribute to mitigating skin dryness and tightness, ultimately making the lancet poke less painful. Following the cleaning process, it is imperative to allow the skin to dry completely before performing the puncture. This not only prevents stinging but also ensures that the blood drop forms properly, optimizing the accuracy of the subsequent steps in the fingerstick procedure.

Applying Blood Sample to the Test Strip

Concluding the fingerstick procedure, the final step involves applying the blood sample to the test strip. Commence by inserting a new test strip into the meter and turning the device on, typically activating and preparing it for the blood sample. Following the finger prick, it’s crucial to ensure the blood drop is sufficiently large to fill the test strip’s designated sample area, guaranteeing an accurate test result.

When applying the blood, carefully drop it onto the edge of the test strip designed to absorb it, avoiding smearing or wiping to preserve the integrity of the sample. Subsequently, wait for the meter to signal, either visually or audibly, indicating that enough blood has been applied. Once the analysis is complete, read the result from the screen. This ensures that the blood sample is applied correctly, leading to accurate and reliable results.

Disposal of Single-Use Testing Supplies

Following the successful execution of the fingerstick procedure, it is imperative to ensure the proper disposal of single-use testing supplies. Used needles and other sharps should be promptly placed in FDA-cleared sharps disposal containers after use.

Maintaining vigilance on the fill level of the sharps disposal container is essential. When the container reaches about three-quarters full, it should be sealed and disposed of according to community guidelines for hazardous waste. Adhering to these safe disposal practices not only fosters personal safety but also protects others from potential health hazards associated with inappropriate disposal of medical waste.

Tips for Reducing Pain and Discomfort

Despite being generally less invasive than a venous blood draw, the fingerstick procedure may still result in some discomfort. Therefore, it’s valuable to be aware of tips to alleviate pain and enhance comfort during the procedure. One effective tip is to warm the fingers with warm water before a fingerstick, as this can improve blood flow and reduce pain.

Furthermore, selecting a lancing device tailored to individual preferences, such as a smaller needle for less pain or a larger device for a better grip, can contribute to decreasing discomfort. Additionally, the application of a cream or lotion specially formulated for people with diabetes can help maintain skin suppleness and potentially reduce pain.

These tips work collectively to make the fingerstick procedure more comfortable, enhancing the overall experience for individuals undergoing this medical process.

Troubleshooting Common Issues

Even with meticulous adherence to the procedure, challenges may arise during capillary blood collection. However, there’s no need to worry. Armed with the right knowledge, these common issues can be effectively addressed. This section will delve into two frequently encountered problems: insufficient blood flow and inaccurate test results.

Insufficient Blood Flow

Encountering insufficient blood flow during capillary blood collection is a common challenge, but practical strategies exist to enhance the procedure’s success. One such approach is arterialization, which involves warming the puncture site, particularly useful for blood gas analysis or cases of poor circulation. You can improve blood flow to the fingertips by washing hands under hot water for at least 4 minutes at approximately 40°C during the sampling procedure.

Additionally, drinking two glasses of water about 30 minutes before the fingerstick procedure can effectively enhance blood flow and volume. To further assist in obtaining a sufficient sample, engage in massaging the finger in a milking motion from the base toward the fingertip. By seamlessly incorporating these strategies, you can address the challenge of insufficient blood flow and optimize the capillary blood collection process.

Inaccurate Test Results

Inaccurate test results are another prevalent problem in capillary blood collection. Many factors can lead to inaccurate blood glucose measurements, such as improper meter coding, test strip deteriorations, and meter handling performance. Moreover, environmental factors like temperature and humidity can significantly impact the performance of blood glucose meters and test strips, potentially leading to inaccuracies.

Furthermore, it’s important to collect laboratory samples in the correct order, starting with hematology specimens, then chemistry specimens, and finally blood bank specimens. This practice can minimize the effects of platelet clumping and enhance the accuracy of specific test results. By understanding these factors, you can take steps to ensure accurate and reliable test results.


In summary, capillary blood collection stands as a vital procedure for medical diagnostics and personal health management. Despite its seemingly straightforward nature, a nuanced understanding and strict adherence to standardized procedures are essential for ensuring accurate results. Each step, from preparing the lancing device to the proper disposal of single-use testing supplies, plays a crucial role. Armed with the knowledge gained from this guide, you are now well-equipped to execute the fingerstick procedure accurately and safely.

Further Reading

Frequently Asked Questions

What is the correct procedure for collecting a capillary specimen?

To collect a capillary specimen, initiate the process by cleansing the designated area with antiseptic. Subsequently, use a sharp needle or lancet to prick the skin of the finger, heel, or another chosen area. Finally, collect the blood through methods such as a pipette, on a slide, onto a test strip, or into a small container. This approach ensures a proper and hygienic collection process, critical for accurate and reliable results.

What is the order of collection for a capillary collection?

When collecting capillary blood specimens, it is advisable to draw the EDTA tubes first to secure a high-quality specimen. Subsequently, proceed to collect other additive tubes and conclude with serum specimen tubes. This sequential order minimizes the risk of cross-contamination of sample tube additives, ensuring the integrity of each specimen.

Why is capillary blood collection preferred over venous blood collection?

Capillary blood collection is favored over venous blood collection for several reasons. It is less invasive, making it a more comfortable option for individuals. The procedure is convenient for various medical conditions and can be easily performed by individuals without medical training.

How can I ensure the accuracy of capillary blood collection?

To ensure the accuracy of capillary blood collection, it is important to maintain clean fingers, obtain sufficient blood volume, and follow standardized procedures closely.

What is the proper way to dispose of single-use testing supplies?

Dispose of single-use testing supplies, such as needles, promptly in FDA-cleared sharps disposal containers after use. This practice ensures safe and proper disposal, significantly reducing the risk of accidental needlestick injuries.