Serology
Serology is the scientific study of serum (the liquid portion of blood after clotting) and other body fluids, specifically focusing on the detection and measurement of antibodies and antigens that are formed as a result of the body's immune response to infections or other foreign substances.
Detect current or past infections
By identifying specific antibodies produced by the body against a pathogen (e.g., antibodies to HIV, Hepatitis B, Rubella, Measles, Syphilis). The type of antibody (e.g., IgM for acute infection, IgG for past exposure/immunity) provides clues about the infection's timeline.
In a diagnostic laboratory, serology tests are primarily used to:
Assess immunity
Determine if an individual has protective antibodies against certain diseases, either from vaccination or previous infection.
Diagnose autoimmune diseases
By detecting autoantibodies (antibodies that mistakenly attack the body's own tissues), though many of these more specialized autoantibody tests fall under the broader "Immunoassay" category.
Blood typing and crossmatching
While often a separate "Immunohematology" section, the principles of antigen-antibody reactions are central to serological blood typing.
Common Serology Tests:
HIV Antibody/Antigen tests
Hepatitis A, B, C antibody and antigen panels
Syphilis (RPR, VDRL, TPPA)
Rubella antibody
Measles (Rubeola) antibody
Dengue, Chikungunya, Zika virus antibodies
H. pylori antibodies
Various autoimmune panels (e.g., ANA, RF)
Infectious Disease Diagnosis
Essential for confirming infections, especially viral ones, and differentiating between acute and chronic stages.
Vaccine Efficacy
Verifying if a vaccine has produced the desired immune response.
Public Health Surveillance
Tracking the spread of infectious diseases in populations.
Parasitology
Parasitology is the scientific study of parasites (organisms that live on or in a host and derive nutrients at the host's expense) and the parasitic diseases they cause.
What it analyzes
Helminths (worms):
Multicellular organisms (e.g., Ascaris, Hookworm, Tapeworm, Schistosoma).
Protozoa
Single-celled organisms (e.g., Giardia, Entamoeba, Cryptosporidium, Plasmodium - malaria parasite).
Arthropods
: (Less common in routine lab, but includes ticks, mites, lice).
Common Parasitology Tests
Stool Ova and Parasites (O&P) Examination
Microscopic examination of stool samples for the presence of parasite eggs, larvae, or adult forms.
Blood Smears
Microscopic examination of thick and thin blood smears for malaria parasites (e.g., Plasmodium species) or other blood parasites (e.g., Trypanosoma, Filaria).
Scotch Tape Test
For pinworm (Enterobius vermicularis) eggs.
Antigen Detection Tests
Rapid tests for specific parasitic antigens (e.g., Giardia, Cryptosporidium, malaria antigens).
Clinical Importance
Diagnosis of Parasitic Infections
Crucial for identifying the specific parasite causing symptoms like diarrhea, fever, anemia, or skin lesions.
Guiding Treatment
Accurate identification is vital for prescribing the correct antiparasitic medication.
Public Health
Plays a role in identifying outbreaks and implementing control measures for parasitic diseases, especially in endemic areas.
Urinalysis
Urinalysis is a routine diagnostic test that involves the physical, chemical, and microscopic examination of a urine sample. It provides a wealth of information about kidney function, urinary tract health, and various metabolic conditions.
Physical Examination
- Color: Indicates hydration, presence of blood, or certain medications.
- Clarity/Turbidity: Suggests presence of cells, crystals, bacteria.
- Specific Gravity: Measures urine concentration, reflecting kidney’s ability to concentrate/dilute.
Microscopic Examination of Sediment:
- Cells: Red blood cells, white blood cells, epithelial cells.
- Casts: Cylindrical structures formed in kidney tubules, indicating kidney disease.
- Crystals: Can indicate kidney stones or metabolic disorders.
- Bacteria/Yeast: Indicates infection.
What it analyzes
Chemical Examination (Dipstick Test):
- pH: Indicates acidity or alkalinity.
⦁ Protein: Can indicate kidney damage or other conditions. - Glucose: Screens for diabetes.
- Ketones: Indicates abnormal fat metabolism (e.g., in diabetes, starvation).
- Blood: Detects red blood cells (hematuria).
- Bilirubin/Urobilinogen: Indicates liver or bile duct issues.
- Nitrite/Leukocyte Esterase: Suggests a urinary tract infection (UTI).
Common Urinalysis Tests
Routine Urinalysis (often includes all three components above)
Clinical Importance
Screening for Kidney Disease
Early detection of kidney damage (e.g., proteinuria, hematuria).
Diagnosis of Urinary Tract Infections (UTIs)
Presence of nitrites, leukocyte esterase, WBCs, and bacteria.
Detection of Metabolic Disorders
Glucose in urine (diabetes), ketones (diabetic ketoacidosis), bilirubin (liver disease).