Chemical Composition of
Blood Plasma
• Terms. Mechanics of investigation.
• High- and low- MW compounds of bl.pl.
• Interpretation of investigations in clinical
practice:
– “Basic set”
– Disorders of the kidneys and internal
environment
– Inflammation
– Liver disorders
Basic terms and mechanics of
investigation
• Serum = liquid remaining after clotting
– usefull for most biochem. tests
• Plasma = whole blood - cells
– emergency tests
– small samples (yield is greater)
– clotting tests
• The mechanics of investigations
– Blood collection: venepuncture
Biochemical abnormalities are
important markers of disease
• Diagnosis = history + examination +
biochemical tests + imaging techniques
• Treatment: monitoring of the response
to therapy in both acute and chronic
disorders
• Prognosis and secondary prevention
• Screening: detecting the non-apparent
disease, eg. PKU or hypothyreosis
Low-molecular weight
compounds of blood plasma
• Cations: Na+, K +, Ca + +
+
• Anions: Cl , HCO3-, HPO42-, HSO4• Metabolites: urea, creatinine, uric acid,
bilirubin
• Nutrients: glucose, FFA, ketones
• Other
High MW compounds of blood
plasma (= proteins)
• According to the function
– oncotic pressure
– clotting factors and fibrinolytic agents
– transport: binding proteins, apoproteins
– antibodies and complement: IgG, IgM
– buffers
– none: enzymes used for diagnostics
• Electrophoretic separation: prealbumin,
albumin, α-, β-, γ-globulines
Internal environment and
the blood buffers
• Basic life conditions:
– isoionia: concentrations of certain ions
must be kept in narrow range
– isoosmia: osmotic pressure is allways the
same in ECS and in cells (in dehydratation
osmotic pressure rises)
– isohydria: pH = 7.35 - 7.45
• Blood buffers: bicarbonate,
hemoglobine, proteins and phosphate
Internal environment
investigation
• Water metabolism: osmolality, Na+
• Acid-base balance disordes: “Astrup“
– taken from arterial blood
– pH, pO2, pCO2, HCO3-, BE, BB, AG, lactate
• Kidney failure: K+, urea, creatinine,
phosphate and sulphate retention
• Respiration failure: pO2 decrease
with/without pCO2 increase
Inflammation
• History + examination
• Changes in the blood count (eg.
leucocytosis) and sedimentation rate
• Non-specific inflammatory markers: eg.
CRP and fibrinogen
• Specific antibodies: IgG or IgM (ELISA)
• Antigen assays: eg. HBsAg
Assays for liver and billiary
tract function and disease
• Parenchyme damage:
– increase in enyzme activity in plasma: ALT,
AST, ALP, GMT
• Alteration of liver function:
– bilirubin accumulation (jaundice)
– alteration of protein synthesis:
hypoalbuminaemia, clotting disturbancies
„Basic set“
• Taken from most of the patients admitted to
hospital
• Give to the physician basic overview about
patient’s metabolic state and organ functions
• Contains:
– Na, K, Cl, glycaemia
– liver set: ALT, AST, bilirubin, (ALP, GMT)
– kidney set: urea, kreatinine
– blood count and FW
– urine examination + sediment