Will Weston - Diagnostic Tests
POTASSIUM
SODIUM
TEST
DESCRIPTION
UREA AND ELECTOLYTES

Major cation of extra cellular fluid (ECF) and has H2O
retaining effect

When excess Na in ECF, more H2O will be reabsorbed from
kidneys

Many functions:

Maintain body fluids

Responsible for conduction of impulses via Na pump (Na in, K
out of cells)

Involved in enzymatic activity

Regulates acid base balance by combining with Cl or CO3
ions.







Most abundant electrolyte in intracellular fluids.
N values within narrow range.
80-90% secreted by kidneys
in tissue breakdown, K enters extra cellular fluid.
N the kidneys can cope with excreting excess intravascular K
Excessive K secretion = hypokalaemia
If urine output <600ml hyperkalaemia may occur.
CREATININE
Compare Serum Levels with urine levels. With an  serum, the
urine is often  and vice versa.







A bi product of muscle metabolism, derived from breakdown of
muscle CP
Amount produced is proportional to muscle mass
Is filtered by glomeruli and excreted in urine
Test considered more sensitive and specific than BUN – blood
urea nitrogen.
Rises later and not influenced by fluid / diet intake.
Useful in evaluation of glomerular function
Compare  result with BUN- if both raised then kidney
disease likely
 LEVEL



































“Hyponatraemia”
Vomiting
Diarrhoea
Gastric suction
Excessive perspiration
Continuous IV dextrose in water
SIADH- syndrome of inappropriate ADH due
to: Surgery (usually 1-2 days excess
secretion), Trauma, Pain, Narcotics
 sodium diet
Burns
Inflammatory reactions
Tissue injury
Psychogenic polydipsia
Salt wasting renal disease
Drugs: Potent diuretics
“Hypokalaemia”
Vomiting
Diarrhoea
Dehydration
Malnutrition/ starvation
Crash diet
Stress
Trauma injury
Surgery
Gastric suction
Intestinal fistulas
Diabetic acidosis
Burns
Renal tubular disorders
Hyperaldosteronism
Excessive ingestion of liquorice
Excessive ingestion of glucose
Alkalsis- metabolic
Drugs- Potassium wasting diuretics,
Thiazides, Steroids, Abs, Bicarbonate, Insulin,
Laxatives, Lithium carbonate, Sodium
polystyrene sulfonate, Salicylates- aspirin
Pregnancy
Eclamsia
May also be  in those with  muscle mass, in
amputees, muscle disease
 LEVEL






























FACTORS  RESULTS
N AMOUNTS
“Hypernatraemia”
dehydration
severe vomiting- water loss is > than
Na loss
CHF
Cushing’s disease
Hepatic F
High sodium diet
Drugs- Cough medicine, Cortisone
preps, Abs, Laxatives, Methyldopa,
Hydralazine, Reserpine


High sodium diet
Drugs

“hyperkalaemia”
oliguria and anuria
acute renal F
IV K in fluids
Addisons disease- adrenocortical
hormone
Crushed injury and burns- with kidney
shutdown
Acidosis- metabolic or lactic
Drugs: Potassium sparing diuretics,
Spironolactone
Triamterene, Abs
Cephaloridine, Heparin, Adrenalin,
Histamine, isoniazid

hydration of pt can
cause false results
overhydration can =
false K deficit through
hemodilution
Dehydration can = K
excess through
hemoconcentration
Use of tourniquet can
K
Hemolysis of
specimen (blood) can
result in high K level
Drugs.

Acute and chronic renal F
Shock- prolonged
SLE
Cancer: Intestine, Bladder, Uterus,
Testes, Prostate
Leukaemias
Hodgkin’s disease
Essential hypertension
Acute MI
Diabetic nepropathy
CHF
Diet rich in creatine- beef
Drugs: Amphotericin C,
Cerphalosporins, Gentamicin,
Kanamycin, Methicillin, Ascorbic acid,
Barbiturates, Lithium carbonate,
Mithramycin, Methyldopa, Glucose,
Protein, Ketone bodies, Triamterene

Red meat in large
amounts
Drugs







Page 1 of 2
Will Weston - Diagnostic Tests
CALCIUM
UREA
TEST
DESCRIPTION

 LEVEL

 LEVEL

FACTORS  RESULTS





Found most abundantly in bones and teeth
Approx 50% is ionised
Only ionised can be used within body
Protein and albumin in blood bind with Ca, thus decreasing
amount of free ionised Ca
In acidosis, more Ca is ionised, regardless of serum level
In alkalosis, most of Ca is protein bound and cannot be
ionised.
Ca is necessary for transmission of nerve impulses and
contraction of myocardium and skeletal muscle.
Causes blood clotting by converting prothrombin to into
thrombin.
Strengthens capillary membrane
With Ca deficit, there is  capillary permeability, causing fluid
to pass through the capillary.
Component of proteins, making up half of plasma proteins
Albumin is synthesised by the liver
Increases osmotic pressure which is necessary for increasing
osmotic (onconic) pressure, which is necessary for maintaining
vascular fluid
 will cause fluid to shift from with in the vessels to the tissues
= oedema


Hypocalcaemia
May cause tetany problems


Hypercalcaemia
May cause cardiac dysrhymias









Diarrhoea
Malabsorption of Ca from GI tract
Extensive infections
Birns
Lack of Ca and vit D intake
OHism
Pancreatitis
Drugs- Cortisone preps, Antibiotics,
Magnesium products, Laxatives, Heparin,
Insulin, Mithramycin, Acetazolamide



Hypervitaminosis D
Hyperparathyroidism
Malignant neoplasm of- bone, lung,
breast, bladder, kidney
Renal calculi
Exercise
OH binge
Milk alkali syndrome
Drugs- Alkaline antacids, Estrogen
preparations, Ca salts, Vit D


















Total protein is composed mainly of albumin and globulins.
Use of total protein serum test is limited unless serum albumin,
A/G ratio, or protein electrophoresis is also performed.
Protein levels needs to be known to determine significance of
its components. With certain disease entities (i.e. collagen
diseases, C, and infections), the total serum protein levels may
be N when the protein fractions are either  or elevated.











“Hypoalbuminaemia”
Cirrhosis of liver
Acute liver failiure
Severe burns
Severe malnutrition
Preeclampsia
Renal disorders
Certain malignancies
Ulcerative colitis
Prolonged immobilisation
Protein losing enterpathies
Malabsorbtion
Drugs- Penicillin, Sulfonmides, Aspirin,
Asorbic acid
Prolonged malnutrition
Starvation
 protein diet
malabsorbtion syndrome
Caner of the GI tract
Ulcerative colitis
Hodgekin’s disease
Severe liver disease
Chronic renal F
Severe burns
Water intoxication.









ALBUMIN





PROTEINS





Diet  / high in Ca /
vit D
IV saline (NaCl)
solution can promote
Ca loss
Drugs
“Hyperalbuminaemia”
Dehydration
Severe vomiting
Severe diarrhoea
Drugs- Heparin

Drugs

Dehydration (hemoconcentration)
Vomiting
Diarrhoea
Multiple myeloma
Respiratory distress syndrome

High fat diet before
the test.







N AMOUNTS

Page 2 of 2