Specimen collection for clinical lab: THE INTRODUCTION>>Classification

Sample collection for clinical lab: THE INTRODUCTION>>Classification


Before we do clinical test, we should collect ideal sample …. Any new clinical lab specialist needs to know how to collect, transport and preserve samples.

Here we will present an introduction but the collection of each sample type will be in separate topic.

To know how to save sample collection in your mind if you want to explain it to someone, you should make  a classification of the samples in you mind …. some people make a classification using the lab units such as serology samples and microbiology samples but this classification is more confusing for me because some sample types can be used for more lab section, for example, blood sample can be used in serology test and you can use blood culture….. But the classification that i use is classification according to the sample types … let me show you, if you write the sample types on paper and watch them for while, you can find that they can be classified into:-

  1. Samples collected from inside the body.
  2. Sample collected from body secretions or wastes and this can be classified into
    1. Samples collected by patient
    2. Samples collected by the lab specialist.

someone may ask me “why you classify sample types by this classification???” ….  You may want to collect 2 blood samples; one as whole blood sample (i.e. blood on anticoagulant) and the other collected to use serum (we will see the difference between serum and plasma) these are different but the 2 sample can be withdrawn in one syringe by phlebotomy but the difference will be in the tube in which you will put the blood …… so, i use this classification because you may use one collection method to get samples for different tests and i will concentrate on how to collect samples first then we will concentrate on the containers to make different samples according to the required tests.

1) Samples collected from inside the body:

As you see the name of this category, the samples obtained from inside the body which means that behind the skin ….. yes, behind the skin where you should break through the skin to obtain your sample.

You can imagine that this means that the patient will feel Pain, Discomfort, and Anxiety and you should know how to deal with the pain, discomfort, and anxiety accompanied sample collection

Common examples of these samples:-

1) Blood samples:- (phlebotomy)

  • This sample type is the most common and most tests is performed using blood sample and this occurs by withdrawing blood from capillaries, veins and some times arteries using syringes or special types of needles
  • It is collected by trained phlebotomists or medical personnel.
  • The process of withdrawing blood is called phlebotomy.
  • Blood withdrawing or phlebotomy takes just few minutes and hurts a bit.
  • It doesn’t need time for recovery.

2) Tissue biopsy:

  • It  involves taking samples of tissue from different sites of the body such as lung, breast, or skin.
  • It is collected by physicians and nurses who have had specialized training.
  • Of course, the patient feel pain more than that of blood sample collection but the pain varies greatly according to the deepness of the site you take sample from.
  • The time of tissue biopsy procedure and time needed for recovery also varies greatly according to the site and procedure.
  • Examples of procedures used for biopsies:
    • Needle biopsy: in this procedure the physician uses a syringe where the needle of the syringe is inserted into the required tissue site then withdraw with the syringe leading to slight discomfort after taking the biopsy and no time for recovery is needed.
    • Open biopsy: collecting sample form tissue by surgery where an incision is made and a portion of a tissue is cut.
    • Close biopsy: it as the open biopsy but the incision is smaller than that of the open biopsy and an instrument is inserted through the incision to guide the surgeon to the desired site and to get the sample.
    • Both open and closed biopsies are performed in a hospital operating room and a local or general anesthetic is used, depending on the procedure, so the patient remains comfortable and recovery may take one to several hours if a general anesthetic is used.

3) Cerebrospinal Fluid (CSF):

  • It this sample type you can get a sample from the Cerebrospinal Fluid using a syringe with special needle and puncture between to vertebrae and into the spinal cord
  • This takes less than half an hour.
  • The patient is asked to lie quietly in a flat position, without lifting his head, for one or more hours to avoid a potential post-test spinal headache.

4) Other bodily fluids: synovial fluid, peritoneal fluid, pleural fluid and pericardial fluid are collected by withdrawing using a syringe and it require resting period after sample collection.

5) Bone Marrow:

  • In this type we get a sample form the marrow which lies inside bones using syringes with special needles … the needle is injected in the iliac crest of the hip bone (in the pelvis) or in the breast bone (i.e. the sternum)
  • It is collected by a doctor or other trained specialist.

2) Samples collected from body secretions or wastes:

a) Samples collected by patient

  • These samples such as urine, feces, sputum, and semen are eliminated naturally from the body, therefore they can be collected by the patient but young children and patients with physical limitations may need assistance.
  • Collecting these samples is painless but it is unpleasant because it involves collection of body wastes and body fluids and also involves body parts and functions that the patient may find that it is embarrassing.
  • The collection of these samples can be collected at home but the patient must be aware with the ideal methods for collecting the sample and the time he/she should bring the sample within but it is more prefer to be collected in the lab to to reduce the errors that may result by the sample handling by the patient.

b) Samples collected by the lab specialist.

These types of samples include Throat, nasal, vaginal fluids and Samples from Open Wounds and Sores and mostly involves  running a swab over the affected area for making bacterial cultures.

Therese samples the patient is not allowed to collect it but it should collect by the lab specialist or any medical personnel who know the ideal procedures

Collecting of these samples are quick and painless but may be uncomfortable and there are no effects after collection

NOTE: you can follow our sample collection topics through the menu Medicine>>Clinical Laboratory tests>>sample collection


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