Updated date:

Blood Sample Collection (Pathology) Role of Phlebotomy.

Author:

In this article you will know about Anemia, it's severity , causes, symptoms and also clenical examination.

PHLEBOTOMY

Introduction -

Correct collection and transportation of samples is necessary for successful isolation of pathogens. Accuracy is required for specimen collection, time and method of dispatch to the laboratory, storage and safe handling. Adequate information about the patient is also required; hence each specimen should be accompanied by a request form. High risk samples must be handled with extra care till it is discarded. Any mistake in tha identification makes the specimen useless and any delay in getting it to the laboratory may yield the wrong result.

Basic Requirement -

  • Tube stand
  • Vacutainer tube, disposable syringes and needles
  • Tourniquet
  • Spirit Swabs
  • Anticoagulants


blood-sample-collection-pathology


Collection Of Blood -

There are three method of blood collection in laboratory --


  1. Venipuncture
  2. Capillary blood by skin puncture
  3. Arterial puncture


VENIPUNCTURE -

Keep on the table all basic requirements.


Procedure :

  • Check the requisition slip. Label the test tubes properly.
  • Select the vein site. (Antecubital fossa)
  • Apply the tourniquet.
  • Clean the area with spirit.
  • Inspect the needle and syringe.
  • The vain is penetrated by positioning the needle at 30° to 40° angle.
  • After blood has been drawn in the syringe or vacutainer tubes release tourniquet.
  • A cotton swab is held firmly over the vein puncture site as soon as the needle is removed.
  • Collect blood in an anticoagulant bulb and mix it carefully, and also collect blood in the tube without anticoagulant.
  • Sample is transferred to the respective department within 90 minutes.


Uses :

Where large amount of blood is required as in

  1. All Hematological tests.
  2. Biochemical test.
  3. Serological & immunological tests.
  4. Bacteriological blood culture.



CAPILLARY BLOOD BY SKIN PUNCTURE -

Selection of site :

  • Adult and children - Ring finger or earlobe
  • Infant's - Great toe or heel


Method :

  • Rub the part with 70% Alcohol or spirit.
  • Make a quick & good stab by using a dry and sterile lancet (A disposable sterile sharp needle also can be used.)
  • The cut should be deep enough (2-4mm) in depth so that blood flows lively without squeezing the stabbed site.
  • By using cotton, the first drop should be wiped away and a separate fresh drop is used for the test.


Uses :

Where less amount blood is required as in --


  1. B.T & C.T
  2. Blood Smear


blood-sample-collection-pathology


ARTERIAL PUNCTURE -

Selection of site :

Radial artery at the wrist, the branchial artery in the elbow, femoral artery in groin.


Procedure :

Same as vein puncture, but it is rare.


Uses :

Serum ammonia, Arterial blood gas, blood pH, PCO2, PO2.


Note :

Blood in the syringe is placed in ice immediately.



blood-sample-collection-pathology


IMPORTANT INSTRUCTIONS FOR BLOOD COLLECTION


  1. Blood should not be collected from cyanotic areas or inflamed areas.
  2. Venous blood is preferred for most hematological examinations.
  3. Tourniquet should be loosened once the needle has been into the vein.
  4. Excess of E.D.T.A, affects both red cell and leukocytes causing shrinkage and morphological change.
  5. Capillary blood should be used when it is not possible to obtain venous blood, as capillary blood may give erroneous results.
  6. The blood should not be obtained by squeezing in case of finger prick, otherwise high values of Hb, R.B.C and leukocyte count are obtained.
  7. After blood collection, perform all the hematological tests within two hours.
  8. Blood should not be kept for long at room temperature. If it is placed in the refrigerator, it should not be frozen.



ANTICOAGULANTS -

For various purposes a number of different types of anticoagulant are available.

1.E.D.T.A :

  • 4gm K3E (E.D.T.A in 100 ml distilled water prepared solution)
  • 0.2 ml solution of E.D.T.A is mixed with 1.8 ml of blood.
  • Prevent coagulation by binding calcium.

uses :

Hematological Examination except L.E cell.

2.CITRATE :

  • Trisodium citrate solution at a concentration of 3.8gm/dl in a ratio of one part to nine part of blood used.
  • Prevents blood coagulation by chelating with calcium.
  • It prevents labile procoagulants.

uses :

PT, PTT.


blood-sample-collection-pathology

3.SODIUM FLUORIDE (NaF)

  • one part of sodium fluoride and three parts if potassium oxalate are mixed to prepare anticoagulant powder
  • 8 gm of this powder is used to collect 2-3 ml of blood.
  • Prevents glycolysis.

USES :

Glucose tests (fasting, random, post prandial & G.T.T)

4.HEPARIN :

  • Powdered 0.2 mg heparin for each ml of blood to be collected.
  • Acts as an antithrombin to prevent the transformation of prothrombin to thrombin and thus the formulation of fibrin from fibrinogen

USES :

Biochemical Tests.


This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2021 Sanju

Comments

Umar on February 20, 2021:

Good information for phlebotomist

Umar on February 20, 2021:

Phlebotomist

Vikas on February 20, 2021:

Great information

Vikas on February 20, 2021:

Great post

Garima verma on February 20, 2021:

Nice information

Garima verma on February 20, 2021:

Nice information

Related Articles