Feasibility Testing Report
Test Title: Prototype Testing using Ortho Clinical Diagnostics Blood Analyzer
Report Author: Ana Peredo
People in Charge: Entire Team
Date: November 25th, 2016
Questions:
1. Will 3V of power create vibration that will resuspend the RBCs and allow for accurate HbA1c test readings?
2. Does vibration allow for barcode reading?
Assumptions:
Power supply is an accurate representation of the power that will be supplied and the vibration that will be created when the electric components are added into prototype. Assumed that 3.0Volts will not lead to any spillage based on previous feasibility testing.
Materials:
Hardware
● Sample Tray Prototype (with exception of electric components)
● 6236B Triple Output Power Supply
● 2 alligator clips
● Human blood (provided by Ortho Clinical)
● Ortho Clinical Blood Analyzer: VITROS 5,1
● 5 mL vacutainer test tubes
○ 5 Plastic tubes with 3mL of blood
○ 1 Glass tube with 3mL of blood
● Pipettor
● 5mL plastic pipettes
Methods:
The power supply was connected to the power socket. One side of one of the alligator clips was clipped to the motor, the other was inserted into the +6V socket. The second alligator cable was inserted into the COM socket in the power supply and the other end was clipped onto the motor (Figure 1). The volt meter knob was left at +6V, the Voltage knob was left at 0 and adjusted gradually after starting each run by looking at the voltmeter, the tracking ratio knob was turned all the way to the right, and the Voltage +20V knob was left unturned.
Figure 1. Power supply with alligator clips connect, showing how knobs were set up for runs.
Each tube had 3mL of human blood. The tubes were inserted in the prototype and the vibration was started. Each tube represented a timepoint. Time 0 was analyzed in the Ortho Clinical Blood analyzer by placing the tube in the original tray. Hemoglobin readings were obtained using the machine. The blood from time 0 tube was transferred to a glass tube (to test glass in the prototype). This was done because there were only five tubes available for blood resuspension testing and each tube represented a timepoint. The four plastic tubes and the glass tubes were inserted in the tray that was vibrating. A tube was removed every 10 minutes and the blood was analyzed by transferring the tube gently to the original tray to interface the machine properly. .
Variables
● Independent Variable:
○ Voltage/Frequency (V, Hz)
○ Volumes (mL)
○ Container Type (Plastic, Glass)
● Dependent Variables:
○ Spillage (Value: Yes or No)
○ Effective HbA1c Test Results (Value: Yes or No)
○ Vibration time (s)
○ Barcode Scanning (Value: Yes or No)
Procedure
Five plastic 5mL vacutainer test tubes were ready for analysis.
a. 3 mL of human blood was obtained in each tube
b. Tube Time 0 was analyzed in the Ortho Clinical analyzer by placing the tube in the original unmodified tray. A hemoglobin test was performed.
c. The blood from test tube time 0 was then transferred using a micropipette and pipettor into a glass test tube of the same size. This was done to test glass test tubes as well, as they fit better in the prototype.
d. The tubes were inserted in the tube slots on the prototype. The power source was turned on the vibration was started. 3V were used to power the motor.
e. In 10 minute increments, one tube was removed from the prorotype and carefully placed in an unmodified tray and the hemoglobin reading was performed. Therefore the final readings obtained were:
i. Plastic - 0 min
ii. Plastic - 20 min
iii. Plastic - 30 min
iv. Plastic - 40 min
v. Glass - 50 min
f. Plastic-50 min was not analyzed as severe sedimentation occurred as seen by measuring the distance of plasma at the top of the tube starting at the start of the sample fluid in the tube.
g. All blood was disposed off following disposal protocol and the hemoglobin data was analyzed through absorbance readings by an Ortho Clinical lab operator.
h. While vibration was being performed in tray, barcode scanning was performed.
Results
Figure 2. Left: Plastic tubes in fixture used for analysis. Right: Plastic tube vs glass tube (smaller diameter so better fit). Bright red is plasma and dark red is sedimented red blood cells.
Plastic and glass tubes used are the same size but apparently there is a small variation in diameter. The fixture was printed using diameters for glass test tubes. At ortho Clinical, they did not have any glass tubes so all analysis had to be done with plastic tubes. The plastic tubes did not fit properly in the prototype as seen in Figure 2 (left). Therefore our data is not representative of accurate vibration effects of the prototype on the samples. Only one glass tube was available. Time 0 blood sample analyzed in plastic tube was transferred to the glass tube given that it was not vibrated. The glass tube could therefore be inserted all the way down in the tube slot as seen in Figure 2 (right).
Not being able to fully place the tube in the slots hindered vibration effects. Sedimentation clearly was observed by the difference in color of plasma and sedimented red blood cells. Severe sedimentation occurred ~25 minutes after being placed on the prototype and being vibrated. Compared to the glass tube that was inserted all the way, the level of sedimentation that occurred with 50 minutes of vibration was much less than with the plastic tube that was not inserted properly. Readings from the machine were analyzed by the Ortho Clinical Operator. Vibration did not move the tray or the tubes so barcode was effectively read from tubes while vibrating on prototype.
Results:
Figure 3. Observations collected by Ortho Clinical lab operator during experiment.
Figure 4. Test readings for the samples for different time points. Sample numbers coincide with numbers depicted in the methods section of this report.
Data indicates that the sample is usable to 20 min. using the prototype tray – this is approximately the same as the settling time initially seen for the sample sitting on the bench without agitation.
Conclusions
● Using a Prototype Tray, whole blood samples were agitated for 20, 30, and 40 min. and the results show that the sample is still “useable” out to 20 min. This means that the vibration tray is not resuspending the RBCs and the readings are similar to those obtained with manual shaking before the test. Ideal time for resuspension is 50 minutes.
● Increased vibration is needed to resuspend RBCs. Future designs need to be implemented on current vibration tray. Motor size will be increased and additional testing will be finished during MSD II.