Medical Sample Collection Techniques

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Questions and Answers

What is the primary reason for performing venipuncture?

To assess respiratory function

To monitor blood pressure

To obtain blood for diagnostic purposes (correct)

To measure blood sugar levels

What is the purpose of collecting a stool sample?

To identify gastrointestinal issues (correct)

To assess blood mineral content

To check for organ function

To analyze blood components

Which vein is most commonly used for venipuncture in the upper limb?

Basilic vein

Radial vein

Cephalic vein

Median cubital vein (correct)

Which method is most suitable for collecting a blood sample from an infant?

Swab of the rectum Signup and view all the answers

Why is venous blood sampling preferred over arterial blood sampling?

Veins have thinner walls and are easier to puncture Signup and view all the answers

What should be done prior to puncturing a finger for a blood sample?

Cleanse the selected area Signup and view all the answers

What is a crucial step before performing a heelstick procedure on an infant?

Pre-warming the infant's heel Signup and view all the answers

What should be done with the first drop of blood during the heelstick procedure?

It should be wiped away Signup and view all the answers

Why should the first drop of blood be wiped away during the blood collection process?

It may contain excess tissue fluid Signup and view all the answers

What is the purpose of using a sterile blood safety lancet during the heelstick procedure?

To avoid contamination Signup and view all the answers

Which site is recommended for finger-prick blood collection?

Pad of the ring finger Signup and view all the answers

What is typically used to seal a stool sample container?

Plastic wrap Signup and view all the answers

What is essential for maintaining the biological integrity of venous blood specimens?

Proper handling and processing of the samples Signup and view all the answers

What type of test is often combined into a blood panel?

Various blood component tests Signup and view all the answers

What should be worn by healthcare staff before performing venipuncture?

Gloves Signup and view all the answers

What should not be done when collecting a blood sample via finger prick?

Puncture the tip of the finger Signup and view all the answers

What is the primary role of cerebrospinal fluid (CSF)?

Acting as a cushion and providing protection to the brain Signup and view all the answers

What is the first step in the lumbar puncture method for CSF collection?

Cleaning the back with disinfectant Signup and view all the answers

Which of the following diseases can be diagnosed using cerebrospinal fluid analysis?

Alzheimer's disease Signup and view all the answers

What is the purpose of centrifuging the cerebrospinal fluid sample?

To separate the sediment from the supernatant for diagnostic purposes Signup and view all the answers

What should be done after completing a blood collection from a newborn?

Elevate the heel and apply a clean cotton piece Signup and view all the answers

What is the appropriate method for disposing of a used lancet?

Disposing in a sharps container Signup and view all the answers

What is the typical volume of CSF collected during a lumbar puncture?

1 - 10 ml Signup and view all the answers

Which of the following actions should NOT be taken during CSF collection?

Using excessive pressure during blood collection Signup and view all the answers

What should be done before collecting samples from lesions?

Clean lesions with surgical spirit or 70% alcohol Signup and view all the answers

Which method is recommended for collecting material from skin lesions?

Scraping with a scalpel blade Signup and view all the answers

What is an important consideration when collecting nail samples?

Include subungual debris in addition to clippings Signup and view all the answers

Which type of hair collection is recommended for infected areas?

Plucking hairs with forceps Signup and view all the answers

At what temperature should skin and nail specimens be stored?

At room temperature Signup and view all the answers

Which bacterium is associated with Impetigo?

Staphylococcus aureus Signup and view all the answers

What do you need to collect from nails for a full laboratory investigation?

Discolored, dystrophic, or brittle parts of the nail Signup and view all the answers

Which organism is linked to Onchomycosis?

Trichophyton rubrum Signup and view all the answers

Which of the following is a fungal infection associated with the area?

Candidiasis Signup and view all the answers

What is the primary purpose of the concentrated oral rinse method?

To isolate pathogens from a saliva sample Signup and view all the answers

Which method involves transferring a sterile foam pad onto a target site for sampling?

Imprint culture Signup and view all the answers

Which of the following viral infections is NOT listed as associated with the area?

Hepatitis B Infection Signup and view all the answers

What is the incubation temperature for the concentrated oral rinse culture method?

37°C Signup and view all the answers

Study Notes

Stool Sample Collection

Stool samples should be collected in a clean, sealable container.
For infants, a stool sample is usually collected with a swab of the rectum.

Blood Sample Collection

Blood is the most widely tested clinical sample globally.
Blood tests are used to determine physiological parameters like mineral content, pharmaceutical drug effectiveness, and organ function.
Blood samples are usually extracted from a vein.

Finger-prick method

The best locations for finger prick are the 3rd and 4th fingers of the nondominant hand.
Avoid the tip, center, and sides of the finger due to less soft tissue, vessels, nerves, and bone proximity.
Avoid puncturing a cold, cyanotic, swollen, scarred, or rash-covered finger.
Cleanse the selected puncture area and massage the finger toward the site.
Make a perpendicular puncture just off the finger pad's center.
Wipe away the first drop of blood because it contains excess tissue fluid.
Collect blood drops by gentle pressure, avoiding excessive pressure or "milking."
Cap, rotate, and invert the collection device to mix the blood.

Venous Blood Collection (Venipuncture)

Venipuncture involves obtaining intravenous access for therapy or blood sampling.
The median cubital vein, located in the cubital fossa anterior to the elbow, is optimal for venipuncture.
Venous blood is advantageous over arterial blood due to its superficial location, thinner walls, larger size, and lower pressure.

Heelstick procedure for infants

The recommended location for blood collection in infants is the heel.
Pre-warm the heel to increase blood flow.
Cleanse the site with an alcohol sponge and dry it with a gauze pad.
Hold the baby's foot firmly to prevent sudden movement.
Puncture the side of the heel across the print lines to allow blood to well up.
Wipe away the first drop of blood and use gentle pressure to produce a rounded drop.
Fill the required microtainer and elevate the heel after collection.
Apply pressure to the puncture site until bleeding stops and tape or Band-Aid if needed.

Cerebrospinal Fluid (CSF) Collection

CSF is a clear, colorless fluid found in the brain and spine.
It acts as a cushion for the brain, providing mechanical and immunological protection.
CSF is used to diagnose diseases like meningitis, encephalitis, tuberculosis, and Alzheimer's disease.

Lumbar Puncture Method

A hollow needle is inserted into the base of the spine under local anesthesia.
The spinal canal's pressure is measured, and a CSF sample is collected.
The patient lies on their side with knees pulled towards the chest and chin tucked downwards.
The back is cleaned with a disinfectant, and local anesthesia is injected.
A spiral needle is injected, and CSF pressure is measured before sample collection.
The needle is cleaned, and a bandage is placed.
The CSF is centrifuged, and the sediment and supernatant are used for diagnosis and culture respectively.

Superficial Sample Collection

Clean lesions with surgical spirit or 70% alcohol before collecting samples.
Include as much material as possible for comprehensive laboratory investigations.

Skin Sample Collection

Collect material by scraping from the edges of lesions, ideally with a scalpel blade.

Nail Sample Collection

Collect subungual debris and nail clippings from discolored, dystrophic, or brittle parts of the nail.

Hair Sample Collection

Pluck hairs from the affected area with forceps and scrape the scalp with a scalpel.
Preferably, the sample should include hair roots, follicle contents, and skin scales.
Hair cut with scissors is unsatisfactory for this purpose.
Sterile toothbrushes may be useful but preclude microscopy on the sample.

Specimen Storage

Skin and nail specimens should be stored at room temperature.

Diseases and Microbes Associated with Infections

Skin Infections:

Impetigo: Staphylococcus aureus
Cellulitis and Erysipelas: Streptococcus pyogenes
Folliculitis: Propionibacterium acnes
Trichomycosis: Corynebacterium tenuis

Nail Infections:

Onchomycosis: Trichophyton rubrum, T mentagrophytes, T megninii
Candida Onchomycosis: Candida albicans.

Oral Cavity Sample Collection

The oral cavity includes the tongue, teeth, gums, bone, and salivary glands.

Diseases Associated with the Oral Cavity:

Fungal infections: Candidiasis, Histoplasmomiasis, Periodontitis, Cryptococcosis
Viral infections: Herpes Simplex, Herpes Zoster, HPV Infection, CMV Infection
Bacterial infections: Linear gingival erythema, Necrotizing Ulcerative, Mycobacterium avium complex

Methods of Sample Collection from the Oral Cavity:

Swab: A sterile cotton swab is rubbed over the lesion tissue and inoculated onto a primary isolation medium like Sabouraud's dextrose agar (SDA).
Concentrated Oral Rinse: The patient holds sterile phosphate-buffered saline in their mouth for 1 minute, and the solution is then concentrated and inoculated on agar.
Imprint Culture: A sterile foam pad dipped in Sabouraud's broth is placed on the target site for 30 seconds and then transferred to an agar for culture.

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Description

This quiz covers essential techniques for collecting stool and blood samples. Learn the proper procedures, tools, and considerations for effective sample collection in a clinical setting. Perfect for students in healthcare and medical fields.