Home › Lab manual › VII. CHEMISTRY *

FINGERSTICK GLUCOSE PROCEDURE **

Effective Date: 
Wed, 07/01/2009
Reviewed: 
Fri, 01/05/2018
Policy: 

Materials:

  • ONE TOUCH ULTRA2 blood glucose meter
  • ONE TOUCH ULTRA glucose test strips
  • BioRad Meter Trax whole blood controls
  • Sterile safety lancet

Principle:

The ONE TOUCH ULTRA system is an in vitro diagnostic test system used for the quantitative measurement of glucose in whole blood. An electrochemical process called chronoamperometry determines the concentration of glucose in a patient’s blood. Chemicals in the test strip using glucose oxidase chemistry mix with the blood sample and a small electrical current is produced. The strength of this current changes with the concentration of glucose in the sample.

Reagents:

  • Each test strip reagent test pad contains:
  • Glucose oxidase (Aspergillus niger)>/=0.08 IU
  • Ferricyanide >/= 22ug
  • Two working electrodes to allow two identical measurements for comparison.
  • Control solution:
  • D-glucose 0.11 %

QUALITY CONTROL:

Whole blood  (Biorad Meter Trax) Low and High control should be run each day of testing or as needed after cleaning or inconsistent results. Run controls in patient mode.

Control values must be within range or results cannot be reported. Enter control values in Harvest LIS.

 

Testing personnel:

Due to State of California Licensure testing may be performed by licensed personnel only. MDs, PA's, FNPs, LVNs, RNs, and CLSs may perform fingerstick glucose testing.

Procedure: 

 

PATIENT TESTING:

  1. Meter should be off. If the meter is already turned on, turn it off by pressing the OK button for two seconds.
  2. Insert a One Touch Ultra test strip with the 3 contact bars facing up into the ONE TOUCH ULTRA 2 blood glucose meter. This will turn on the meter. A black start up screen and then a code number will show in the display. The code number on display must match the number on the test strip package. If it does not, press the up or down button until the number matches. When the number matches, press “OK”.
  3. The screen will advance to the “APPLY BLOOD” screen in 5 seconds or if you press “OK”.
  4. Prepare the patient’s finger for the finger-stick. Clean off the test site with an alcohol pad, then dry with a clean gauze pad.
  5. With a quick motion, prick the test site and gently press to obtain a drop of blood (at least one microliter).
  6. Gently press the finger above the test site to obtain a drop of blood of at least one microliter on the fingertip.
  7. Touch and hold the drop of blood to the narrow channel in the top edge of the test strip. Blood will be drawn into the strip. Continue to hold the drop of blood to the top edge of the test strip until the confirmation window is full.
  8. The meter counts down from 5 to 1. The blood glucose level will be displayed along with the date, time and unit of measure.
  9. Record the result in the Fingerstick Glucose Test log and in Orchard Harvest LIS.
  10. If the value is critical (<50mg/dl or >200mg/dl, report by phone to an RN or the patient’s provider. Document the phone call in the comments section for the result in Orchard/Harvest. “Glucose phoned to xxx at (time) on (date).”

NOTE:

  • Do not bend the test strip
  • Do not smear or scrape the drop of blood with the test strip
  • Do not press the test strip too firmly against your puncture site
  • Do not apply more blood to the test strip after you have moved the drop of blood away
  • Do not move the test strip in the meter during a test
  • Testing supplies (test strips and control solution) are ordered from McKesson by the laboratory

Expected results
This meter is plasma calibrated. Results should agree within 20% of a venous blood sample tested on a chemistry analyzer in the laboratory. Plasma calibrated capillary glucose values obtained by the OneTouch Ultra2 Meter will be about 12% higher than whole blood calibrated meters.
 

Recent meals; hematocrit >55% or <30%; severe dehydration; and ambient room temp near 18C may cause capillary glucose values to be >20% different than venous lab tested values.

Fasting: 70-105 mg/dL
Random: 70-110 mg/dL
1 hour post prandial: <160 mg/dL
2 hours post prandial: <120 mg/dL
Linearity : 20-600mg/dl

Cleaning and maintenance of glucometer
To clean the meter, wipe the surface with a soft cloth dampened with water and mild detergent. Do not use alcohol or other solvents to clean the meter. Do not get liquids, dirt, dust, blood, or control solution inside the meter through the test port or the data port.

Batteries
The One Touch Ultra meter uses two 3.0 Volt CR 2032 lithium batteries. One powers the backlight and one powers the meter only. Batteries can be obtained on the top shelf of the laboratory refrigerator.

The meter displays a battery icon in the upper right corner of the display for a low battery message to indicate the condition of the meter battery only. When the battery icon appears, there is enough power for a minimum of 100 more tests. When the LOW BATTERY screen message appears, there is not enough battery power remaining to perform a test and a new battery must be installed. See glucometer booklet for battery replacement instructions.

Limitations

  • Fresh capillary blood may be collected into heparin-containing test tubes if the blood is used within 10 minutes. Do not use other anticoagulants or preservatives.
  • Patients undergoing oxygen therapy may yield falsely low results.
  • Test results may be falsely low of the patient is severely dehydrated, in shock, or in a hyperosmolar state (with or without ketosis). Critically ill patients should not be tested by blood glucose meters.
  • Interferences: Acetaminophen, salicylates, uric acid, ascorbic acid (vitamin C), and other reducing substances (when occurring in normal blood or normal therapeutic concentrations) do not significantly affect results. However, abnormally high concentrations in blood may cause inaccurately high results.