Clinical Chem 1st lec Flashcards
UNITS and VALUES
- pH: 7.3- 7.45
- Glucose: 11mmol/l
- Sodium: 136-148 mEq/l
- Potassium: 3.5-5 mEq/l
- Specific gravity: 1.005-1.030
- Blood electrolytes: mEq/l
- Kidney filtration rate: 100ml/min
- Urea: 2.5-6.6 mmol/L
- Creatinine: 60-120 umol/L
TESTS
- Kidney function tests (blood, urine, GFR)
- Kidney Function Tests (Glomerular dysfunction, tubular dysfunction)
- Blood test
- Creatinine clearance test (late stage kidney problem) : 24hr urine and blood sample, 120-140ml/min
Calculation is urine creatine x urine volume (ml) divided by plasma creatinine x collection period (min) - GFR = Kx (140-Age) x Bodyweight over/divided by Serum creatinine (umol/L)
[Cockcroft and Gault Formula]
HAEMATURIA (blood in pee)
- UTI
- Kidney stones
- Glomerulonephritis
- Prostatitis (and BPH)
- Trauma
- Ca kidney/bladder
- STDs
PROTEINURIA
- Renal disease (Nephrotic syndrome, nephritis)
- Renal impariment secondary to (Hypertension, pre-eclampsia, CCF)
GLUCOSURIA
- D/t blood glucose level elevation (DM)
- D/t reduced renal absorption (renal tubular disease)
KETONURIA
- Uncontrolled DM (Diabetic ketoacidosis)
- Starvation
Urobilinogen and Urobilin
- Urobilinogen formed in GI tract
- Small amount excreted in urine and is colourless
- Upon exposure to air becomes UROBILIN
- Urobilin is the yellow coloured compound!
- Increased conc in hepatic disease (Hepatocellular damage, hapititis, haemolytic anaemia)
Bilirubin
- End product of haemoglobin catabolism
- Presence of bilirubin in urine is always pathological
- Indicative of hepatic or biliary disease
Specific gravity
- Used to monitor concentrating and diluting power of the kidney
Leucocytes
- In urine indicates bladder or renal infection
Nitrite
- In urine due to gram-negative bacteria (UTI)
Electrolytes and Ions
- Aids water balance
- Maintanence of acid-base balance required for normal cellular activities
- Production of action potentials
- Cofactors for optimal activity of enzyme
Blood electrolytes
Measured as mEq/l
- ECF: Na+ , Cl-
- ICF: K+, Mg 2+, Phosphates
Sodium
NR: 136-148 mEq/l
Fluid and electrolyte balance
Conduction of action potentials in neurones and muscle fibres
Acute hyponatraemia (Usually d/t excess water accumulation in the body, eg excessive sweating, vomiting, diarrhea, diabetes, diuretics, adrenal insufficiency, inappropriate ADH secretion) leads to swelling of brain cells causing cerebral oedema and confusion, seizures, coma Acute Na <120mmol/l
Chronic - Often asymptomatic or present with mild confuion and nausea
-cerebral adaptation has occured with brain cells excreting intracellular osmoles to limit cell swelling. over rapid correction of chronic may produce profound neruological abnormalities.
Hypernataemia occurs w water deprivation (resulting in conc. of all blood constituents) or excessive aldosterone (COnns syndrome)
Causes CELLULAR DEHYDRATION
- If severe can cause confusion and coma, risk of cerebral haemorrhage
Potassium
NR: 3.5-5.0 mEq/l
Helps regulate pH
Plays a role in resting membrane potentials
Controlled mainly by ALDOSTERONE
HYPOKALAEMIA often d/t vomiting and diarrhea, or reduction of redistribution
- Also occurs in hyperaldosteronism (Conn’s syndrome), kidney disease, diuretic therapy
1º symptoms: Muscle weakness and paraesthesia w risks of cardiac arrhthmias and ventricular failure
Hyperpolarisation of cell membrane which impairs the ability of cells to generate action potential in excitable tissues such as muscles and nerves
HYPERKALAEMIA Occurs w - excessive intake, renal failure, aldosterone deficiency (Addison’s), crushing injuries
- often asymptomatic but 1º risk of arrhthmias and sudden death
- Reduces the polarisation of the cell membrane so that it falls closer to the threshold for depolaarisation thereby making cells more excitable
