Applications in Clinical Chemistry

Study Notes

Electrophoresis is used in clinical chemistry laboratories for:
- Serum Protein Electrophoresis (SPEP) to assess protein distribution in serum for diagnosis of liver disease, kidney disease, and multiple myeloma
- Hemoglobin Electrophoresis to identify and quantify hemoglobin variants for diagnosis of hemoglobinopathies like sickle cell anemia
- Lipoprotein Electrophoresis to separate lipoproteins for assessing lipid metabolism disorders
- Isoenzyme Analysis to diagnose tissue damage or disease
Chromatography is used in clinical chemistry laboratories for:
- Drug Testing to identify and quantify drugs and their metabolites in biological samples
- Toxicology to detect and measure toxins and poisons
- Therapeutic Drug Monitoring to monitor therapeutic drug levels in patients' blood
- Newborn Screening to identify metabolic disorders in newborns
- Amino Acid Analysis to quantify amino acids in biological fluids and tissues
- Hormone Analysis to measure hormone levels in blood or urine
- Carbohydrate Analysis to analyze sugars and other carbohydrates in various samples

Electrophoresis:
- Advantages: high resolution and separation efficiency, versatility, minimal sample preparation, relatively fast and easy to perform
- Limitations: may require specialized equipment, can be labor-intensive, requires staining or detection methods to visualize separated bands
Chromatography:
- Advantages: high sensitivity and resolution, versatility, quantitative and qualitative analysis, automation potential
- Limitations: can be time-consuming, may require specialized equipment, optimization of conditions can be challenging

Electrophoresis:
- Sample Preparation: proper sample handling and preparation are crucial for accurate results
- Buffers: choose the appropriate buffer for optimal separation and resolution
- Staining/Detection: select the appropriate staining or detection method to visualize the separated molecules
- Interpretation: careful analysis and interpretation of electrophoresis results are essential for accurate diagnosis and monitoring
Chromatography:
- Sample Preparation: proper sample preparation is critical to remove interfering substances and ensure optimal chromatography
- Choice of Stationary and Mobile Phases: selection of the appropriate phases is essential for achieving the desired separation
- Detection: choose a suitable detector to identify and quantify the separated components

Mass spectrometry is a powerful analytical technique used to identify and quantify the chemical components of a sample based on their mass-to-charge ratio (m/z)
Core principles: convenience, patient empowerment, reduced healthcare costs, improved patient satisfaction

Accuracy and Precision: some POCT devices may not be as accurate or precise as laboratory tests
Limited Test Menu: not all tests can be performed at the point of care
Operator Error: improper use of POCT devices can lead to inaccurate results
Quality Control: regular calibration and quality control are essential to maintain accuracy
Cost: some POCT devices can be expensive, especially for single-use tests

Regular Calibration: devices should be calibrated according to manufacturer instructions
Control Testing: testing with known control samples helps verify the accuracy of the device
Proficiency Testing: participation in external proficiency testing programs assesses the performance of both the device and the operator
Training and Certification: healthcare professionals using POCT devices should be adequately trained and certified
Documentation: all POCT results and quality control data should be carefully documented

Expanded Test Menu: a wider range of tests becoming available at the point of care
Laboratory Diagnosis: lipoprotein subclass analysis and apolipoprotein measurements may be used in certain situations

Familial Hypercholesterolemia (FH):
- Heterozygous FH: one mutated gene, LDL typically 200-400 mg/dL
- Homozygous FH: two mutated genes, LDL often >500 mg/dL
- Laboratory Diagnosis: lipid panel, genetic testing
- Complications: early onset of atherosclerosis and cardiovascular disease
Lipid Panel:
- Components: total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides
- Patient Preparation: fasting for 9-12 hours before the test is usually required for accurate triglyceride measurement

Lipids play a central role in CVD risk assessment
Other risk factors for CVD: family history, ethnicity, obesity, physical inactivity, diet, stress, sleep apnea, chronic kidney disease, inflammatory markers (e.g., C-reactive protein)
Framingham Risk Score (FRS) is used to estimate CVD risk
CVD risk assessment should be personalized, taking into account individual risk factors and preferences