Question

1. What is the rationale of wiping off the first drop of blood during capillary blood collection?

2. What is the effect on the test results if the first drop is used?

3. Enumerate at least three (3) causes of hemolysis in capillary puncture samples. Indicate what extra steps you might need to take with the following patients.

a. Anticoagulated patient

b. Resistant patient

c. Psychiatric patient

d. Obese patient Patient with damaged or collapsed veins

e. Patient with damaged or collapsed veins  

Answer 1

1)Rationale of wiping off the first drop of blood during capillary blood collection:

The first drop tends to contain excess tissue fluid,tissue extracts and alchohol residue which will alter the accuracy of the result.

2)Taking first drop of capillary blood for testing will cause inaccurate test results,as it contain excess tissue fluid and skin debris.

3) Causes for hemolysis in capillary puncture samples:

• Milking(squeezing) the site before capillary puncture.
• Using scooping motion to take capillary blood against the surface of the skin.
• Puncturing on swollen or previously punctured site.
• Not allowing alcohol to air-dry completely.

Extra steps needed to take while collecting sample in following patients:

a.Anticoagulated patients:

In anticoagulated patients

• Do not squeeze the site before puncturing the site.
• Do not perform scooping motion to take samples.
• A small puncture with small bore needle is preffered inorder to avoid hematoma and excessive bleeding.
• After the procedure apply pressure until blood flow ceases and apply bandages.

b.Resistant patient:

• In a understandable language convince the patient about the need and benefits of testing.
• Assure the patient that very minimal amount of blood required for testing will be drawn.
• Try to finish the procedure as early as possible.
• Still if he or she is resistant to undergo testing, do not force the patient,get procedure refusal form signed.

c.Psychiatric patients:

• Make a calm and pleasant environment for patient before taking sample.
• Keep a good eye contact and rapport with the patient inorder to get a confidence.
• Always encourage the presence of patient guardian before performing procedures.
• Use of divertional theraphy to divert the patients attention is helpful.

d.Obese patient with damaged or collapsed veins:

• Perform capillary refill test,and do puncture at site where the test result is less than 3seconds.
• Use earlobe or heels alternatives to fingers.
• Warming up the site with a temperature less than 42°C for a duration of 3-5minutes.
• Placing down the puncture site below the heart level,it increases blood flow to the punctured site.

e.Patient with damaged or collapsed veins:

• Perform the capillary refill test to check blood flow to the site of puncture.
• Warming the puncture site prior to procedure for 3-5 minutes with moist towel or commercially available warming device increases blood flow at site.
• Facing down the punctured finger will increase the flow of blood due gravitational force.