T1 Clinical Chemistry

#type/tutorial

cannot refrigirate cuz will form crystals which is not the gout which gives false results

  1. What is the suitable specimen for this case?
  2. Reason?
  3. Name the procedure used to obtain the mentioned specimen 4. What are the key precautious steps when collecting this type of specimen?

CLINICAL SCENARIO 1

A 19-year-old university student is brought to the Emergency Department with a high fever, severe headache, confusion, and a stiff neck. The clinician suspects bacterial meningitis and needs to collect spinal fluid.

CEREBROSPINAL FLUID i) Blood-brain barrier (BBB) - systemic blood or urine samples do not accurately reflect localized central nervous system (CNS) Infections, inflammatory processes, or hemorrhages in real time

ii) Lumbar Puncture (LP) (spinal tap) - performe in the lower lumbar spine, typically between the L3/L4 or L4/L5 intervertebral spaces.

ili) STAT (emergency) specimen

  • hand-delivered to the lab immediately (within 15-30 minutes) and processed upon arrival - room temp (20-25C); NEVER refrigerate for microbiology

  • lab staff must handle CSF in a Class I Biosafety Cabinet (BSC) using full PPE (gloves, lab coat, face shield/safety glasses)

CLINICAL SCENARIO 2

A 58-year-old male arrives at the clinic with an acutely swollen, hot, and painful right knee joint. He is unable to bear weight. The physician needs to aspirate fluid from the joint space to differentiate between gout and a septic (infected) joint.

SYNOVIAL FLUID i) Pathological changes eg., crystal accumulation or severe joint infections, occur directly inside the joint space

ii) Arthrocentesis (joint aspiration)

  • performed directly into the affected joint cavity
  • aseptic technique - thoroughly disinfect the skin overlying the joint before needle insertion

iii) Transport the sample immediately at room temp (20-25C); DO NOT refrigerate samples for crystal analysis

iv) Collected fluid must be mixed gently with sodium heparin or liquid EDTA for cell counts and crystal analysis; avold powdered anticoagulants

CLINICAL SCENARIO 3

A 32-year-old pregnant woman at 16 weeks of gestation requires diagnostic fluid sampling due to abnormal ultrasound findings and high risk of fetal abnormalities.

AMNIOTIC FLUID i) Targeted prenatal assessment - to evaluate fetal genetic abnormalities, chromosomal disorders, severe fetal infection, or fetal lung maturity when non-invasive maternal blood or ultrasound tests indicate high risk

ii) Amniocentesis - transabdominal aspiration of fluid from the amniotic sac

iii) Aseptic technique & ultrasound guidance- to avoid puncturing the fetus, placenta, or umbilical cord, and to prevent maternal-fetal infection

  • avoid maternal blood contamination

  • specimens must be collected into amber colored tubes or immediately wrapped in aluminum foil upon collection - photo-labile - room temp/ iced; NO frozen sample for genetic karyotyping

CLINICAL SCENARIO 4

A 65-year-old female presents to the emergency department with progressive shortness of breath, a persistent dry cough, and sharp chest pain that worsens when taking a deep breath. A chest X-ray reveals a large accumulation of fluid in the space surrounding her right lung (pleural effusion). The physician needs to obtain fluid to determine whether the buildup is due to heart failure, infection (pneumonia), or malignancy.

PLEURAL FLUID i) Pleural fluid accumulates directly between the visceral and parietal membranes of the lungs - provides an immediate, definitive diagnosis while simultaneously relieving the patient's breathing difficulty.

ii) Thoracentesis (pleural aspiration/ chest tap) - performed through the intercostal space on the posterior chest wall

iii) Ultrasound guidance & aseptic technique avoid introducing skin bacteria into the pleural cavity

  • prevent accidental puncture of the lung parenchyma

  • transport at room temp

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