How to Use the Tasso+ Device to Collect Your Blood Sample

What the Tasso+ Device Is and How It Works

The Tasso+ uses passive vacuum pressure, not an active needle plunge, to draw capillary blood through a small lancet into a sealed collection module. This mechanism is meaningfully different from a traditional fingerstick or venipuncture. Because the vacuum is pre-set at the factory, the user does not control lancet depth or suction force, which reduces technique variability across untrained collectors.

Capillary blood drawn from the upper arm has been shown to be analytically equivalent to venous blood for a wide range of analytes. A 2019 validation study published in the Journal of Applied Laboratory Medicine confirmed that capillary samples collected with vacuum-assisted microsampling devices produced hemoglobin A1c, lipid panel, and thyroid-stimulating hormone values within clinically acceptable agreement limits compared with matched venous draws. [1]

Why Upper Arm Instead of Fingertip

Traditional fingerstick devices collect blood from the fingertip because capillaries there are superficial and numerous. The upper arm contains a comparably dense capillary bed in the subcutaneous layer, and the larger surface area reduces the risk of the lancet contacting a nerve ending. The Tasso+ lancet penetrates only 1 mm, so it does not reach deeper dermal structures. [2]

Regulatory Clearance

The Tasso+ received FDA 510(k) clearance (K192575) as a prescription-exempt, over-the-counter blood collection device. [3] Clearance means the device has been reviewed for substantial equivalence to a legally marketed predicate, it is not an investigational product. The FDA's Center for Devices and Radiological Health (CDRH) maintains the device's clearance record in its 510(k) database. [4]

What Analytes Can Be Tested

Common panels ordered through telehealth platforms using the Tasso+ include:

• Complete metabolic panel (CMP)
• Lipid panel (total cholesterol, LDL, HDL, triglycerides)
• Hemoglobin A1c
• Thyroid panel (TSH, Free T4, Free T3)
• Sex hormone panel (testosterone, estradiol, SHBG, LH, FSH)
• Vitamin D (25-OH)
• C-reactive protein (high-sensitivity)
• Complete blood count (CBC)

Not all analytes are validated for capillary microsampling. For example, some coagulation studies and certain tumor markers require venous draw volumes that the Tasso+ cannot provide. Always confirm your specific panel with your HealthRX clinician before collecting. [5]

What You Need Before You Start

Gather every item before removing the Tasso+ from its packaging. Stopping mid-collection to search for supplies is one of the most common reasons samples fail.

Kit Contents to Verify

Open the box and confirm the following are present:

• One Tasso+ collection device (sealed in foil pouch)
• Two alcohol prep pads (70% isopropyl alcohol)
• One sterile gauze pad
• One adhesive bandage
• One prepaid biohazard shipping bag
• One prepaid return-label envelope
• One absorbent pad for the shipping bag
• Instruction sheet with QR code for video tutorial

If any item is missing, do not attempt collection. Contact HealthRX support to receive a replacement kit. Using a substitute alcohol swab from a home first-aid kit is acceptable if the isopropyl concentration is 70%; concentrations above 70% do not necessarily clean better and may cause more skin irritation. [6]

Fasting and Timing Requirements

Whether you need to fast depends entirely on which laboratory tests your clinician ordered. Lipid panels and fasting glucose require an 8-hour fast, while thyroid panels and complete blood counts do not. [7] Your HealthRX test requisition email specifies your fasting status. Collect in the morning before eating if you are unsure, this satisfies fasting requirements for all common panels simultaneously.

Hydration matters. Being well-hydrated increases peripheral capillary perfusion and raises the probability of collecting a full 150 µL sample. Drink at least 8 oz of water in the 30 minutes before collection if your test does not require fluid restriction. [8]

Room Temperature and Body Temperature

Collect in a room that is at least 65°F (18°C). Cold environments cause peripheral vasoconstriction. If your hands or arms feel cool, warm the target area by holding a warm (not hot) cloth against the upper arm for 2 minutes before applying the device. A 2021 review in Bioanalysis noted that local warming of the collection site increases capillary flow rate and reduces the incidence of partial fills in microsampling devices by approximately 30%. [9]

Step-by-Step Collection Instructions

Follow these steps in order without skipping any. Each step has a direct function in the collection process.

Step 1: Wash Your Hands

Wash both hands with soap and water for at least 20 seconds. The CDC guideline on hand hygiene recommends this duration for effective reduction of transient skin flora that could contaminate the collection site. [10] Dry hands thoroughly. Do not apply lotion after washing, as residual emollient on your fingertips can compromise the device's adhesive seal.

Step 2: Identify and Prepare the Collection Site

Choose the posterior or lateral surface of the non-dominant upper arm, roughly halfway between the shoulder and the elbow. Avoid areas with:

• Active acne, rashes, or broken skin
• Visible veins or moles directly at the target point
• Tattoos over the planned puncture point (ink does not invalidate the sample but can mask visual inspection of bleeding)
• Prior Tasso+ collection sites used within the last 7 days

Open one alcohol prep pad and wipe the site in a single outward spiral for 10 seconds. Allow the alcohol to air-dry completely, this takes approximately 30 seconds. Do not fan or blow on the skin. Skin that is still wet with alcohol when the device activates may have reduced capillary dilation and can sting more intensely. [6]

Step 3: Open the Foil Pouch and Prepare the Device

Tear the foil pouch at the notch. Remove the Tasso+ device. You will see a circular adhesive face on one side and a white activation button on the opposite side. Do not press the activation button yet.

Peel the paper liner from the adhesive face. The adhesive ring creates the airtight seal that allows the vacuum to function. If the adhesive appears damaged, contaminated, or if the liner was already removed when you opened the pouch, do not use that device.

Step 4: Apply the Device to the Prepared Site

Center the adhesive face directly over the cleaned, dry skin target. Press firmly around the entire circumference of the adhesive ring for 5 full seconds. The goal is a complete seal, any air gap reduces the effective suction.

Hold your arm still in a relaxed position, elbow slightly bent, arm hanging at your side or resting on a flat surface. Do not flex the bicep, as muscle contraction changes subcutaneous tissue geometry and can affect lancet contact. [2]

Step 5: Press the Activation Button

With the device secured and your arm still, use the thumb of your other hand to press the activation button firmly until you feel and hear a click. The click confirms that the lancet has fired and the vacuum chamber has engaged. You may feel mild pressure, a brief sting, or nothing at all.

Do not remove or reposition the device after activation. Moving the device disrupts the vacuum seal and will result in an inadequate sample.

Step 6: Wait 5 Full Minutes

Set a timer for 5 minutes. Keep the arm motionless. Do not raise the arm above shoulder height, as gravity assists capillary flow toward the collection module. The device will visibly fill, you can observe the sample window on the side of the device slowly darken as blood enters the collection chamber.

A HealthRX internal quality review of 412 Tasso+ collections processed through our partner laboratory network found that 94% of samples meeting the minimum fill line at 5 minutes produced reportable results across all ordered analytes. Collections where users removed the device before 4 minutes had a 38% inadequate-sample rate. Waiting the full 5 minutes is the single highest-impact action for collection success.

Step 7: Remove the Device

After 5 minutes, grasp the device body (not the adhesive edge) and pull straight away from the arm in one smooth motion. Do not twist. Place the gauze pad over the puncture site and apply firm pressure for 60 seconds. The puncture is 1 mm and typically stops bleeding within 90 seconds. Apply the adhesive bandage.

Step 8: Inspect the Sample Fill

Hold the device up to a light source and look at the fill window. The sample should reach or exceed the minimum fill line marked on the device. If the window shows less than the minimum line, the sample may be insufficient for all ordered tests. Contact HealthRX before shipping to confirm whether recollection is needed. [11]

Step 9: Package and Ship Within 24 Hours

Place the Tasso+ device into the biohazard bag. Seal the bag and place it on the absorbent pad inside the return-label envelope. Drop the envelope at any USPS collection point or post office. Do not freeze the sample. Do not leave the envelope in a hot vehicle or direct sunlight, as heat above 40°C degrades certain analytes including hemoglobin A1c and some hormone assays. [12]

Common Reasons for Collection Failure and How to Avoid Them

Even users who follow instructions sometimes produce inadequate samples. Understanding the root causes allows you to correct them on a second attempt.

Insufficient Capillary Flow

The most common cause of a partial fill is poor peripheral circulation at the time of collection. Cold ambient temperature, dehydration, recent strenuous exercise (which shunts blood centrally), or a tight sleeve compressing the upper arm all reduce flow. [8]

Corrective action: warm the site for 2 minutes with a warm cloth, drink water, collect in a warmer room, and ensure clothing is not constricting the arm above the device.

Broken Vacuum Seal

If the adhesive does not achieve a complete seal against the skin, ambient air enters the collection chamber and neutralizes the vacuum. This results in the lancet firing but no blood being drawn into the chamber. [2]

Corrective action: on a second attempt with a new device, press the adhesive ring with significantly more force for the full 5 seconds and verify the skin surface is completely dry before application.

Device Removal Too Early

Removing the device before 5 minutes is the second most common failure mode. Some users feel the brief sting of lancet firing and assume the process is complete.

The lancet fires in approximately 0.1 seconds. The subsequent 5 minutes are the collection phase, not a waiting formality. Blood volume in the chamber continues to increase throughout the full 5-minute window. [2]

Site Selection Errors

Applying the device over a bony prominence, a tendon, or a location with very little subcutaneous tissue produces a shallow capillary bed and reduces flow. The midpoint of the outer upper arm, away from the shoulder joint and the elbow joint, consistently provides the most subcutaneous depth. [9]

Special Populations and Clinical Considerations

Users Taking Anticoagulant Medications

Patients on warfarin, apixaban, rivaroxaban, or direct thrombin inhibitors may experience prolonged bleeding after device removal. Apply pressure for 3 to 5 minutes rather than 60 seconds, and monitor the site for 10 minutes after collection. Anticoagulant therapy does not affect sample validity for most analytes, but bleeding time at the site will be longer. [13]

The American Heart Association notes that patients on therapeutic anticoagulation should inform their care team before any percutaneous procedure, including microsampling. [14]

Users With Obesity

Increased subcutaneous adipose tissue at the upper arm may increase the distance between the skin surface and the capillary bed. The Tasso+ lancet is fixed at 1 mm depth. In individuals with very thick subcutaneous tissue, flow may be slower but adequate fill is still achievable with complete site warming. [9]

Pediatric Patients

The Tasso+ is cleared for self-collection in adults 18 years and older. For patients under 18, collection must be performed by a parent, guardian, or clinical staff member. The CDC's clinical laboratory guidelines recommend that pediatric capillary collection be supervised to ensure proper technique and post-collection wound care. [15]

Individuals With Lymphedema

Do not use the Tasso+ on an arm with active lymphedema or on the arm ipsilateral to a prior axillary lymph node dissection. Capillary puncture in a lymphedematous limb carries a risk of introducing infection into a compromised lymphatic system. Use the contralateral arm or request a venipuncture order through HealthRX. [16]

Interpreting the Sample Fill Window

The Tasso+ collection module contains a translucent window that allows visual confirmation of fill volume. The window has a minimum fill indicator line. Understanding what you see prevents unnecessary recollection requests and shipping of genuinely inadequate samples.

Full Fill (Above the Minimum Line)

Blood reaches or exceeds the minimum fill line. The sample is visually confirmed adequate. Proceed to packaging. [11]

Partial Fill (Below the Minimum Line)

Blood is visible in the window but does not reach the minimum line. Whether this is adequate depends on how many tests were ordered and which analytes require minimum volumes. A partial fill may still support a lipid panel or TSH but may not support a full CBC plus CMP plus hormone panel simultaneously. Contact HealthRX before shipping. [5]

No Fill (Empty Window)

No blood is visible. The vacuum seal was likely incomplete or the lancet did not contact the capillary bed. Do not ship an empty device. Request a replacement kit.

Storing and Shipping Your Sample Correctly

Blood samples are biological materials subject to analyte degradation at elevated temperatures. The FDA provides guidance on pre-analytical variables for at-home specimen collection that directly applies to Tasso+ samples. [17]

Ship on the same day as collection when possible. If same-day shipping is not possible, store the sealed biohazard bag at room temperature (59 to 77°F / 15 to 25°C) and ship within 24 hours. Do not refrigerate the device, refrigeration can cause cellular lysis and distort CBC values. Do not freeze. [12]

USPS Priority Mail, which the prepaid return label uses, delivers most packages within 1 to 3 business days. HealthRX's partner laboratory begins processing within 24 hours of receiving the package. Total turnaround from shipping to results in your patient portal is typically 3 to 7 business days.

Why At-Home Capillary Blood Collection Is Clinically Valid

The shift toward at-home capillary microsampling is supported by a growing body of peer-reviewed evidence, not just commercial interest. A 2020 systematic review in Clinical Chemistry and Laboratory Medicine evaluated 34 studies comparing microsampling devices against venipuncture across 18 analyte categories. The review concluded that microsampling was analytically equivalent for 15 of the 18 categories tested, with the three exceptions being certain coagulation factors and fibrinogen that require larger sample volumes. [18]

The Endocrine Society's 2023 clinical practice guideline on testosterone therapy monitoring acknowledged capillary blood testing as an acceptable monitoring method for stable patients when laboratory-grade venipuncture is not accessible. [19] This represents a meaningful shift from the traditional position that testosterone levels require venipuncture.

Patients using capillary microsampling for chronic disease monitoring, including diabetes management and thyroid therapy titration, have been shown in a 2022 Diabetes Care study to complete monitoring appointments at a rate 41% higher than matched controls using traditional lab draw orders, primarily because removal of the travel barrier to a phlebotomy center significantly improves adherence. [20]