Results interpretation
Full Blood Count (FBC)
Full blood count looks at the number of cells in the blood , their size and each specific type.
The common measurements and values of an FBC are below…
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White blood cells
Haemoglobin (Hb)
 Men
 Women
Mean cell volume (MCV)
Haematocrit
4-11 x 10 /L
Platelets
150 -300 x 10 /L
13-18g/dl
11.5- 16g/dl
80-100 fL
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Red blood cells and anaemia
Red blood cells carry oxygen around the body in haemoglobin (Hb). A low haemoglobin is
termed anaemia.
Anaemia is classified on the size of the red blood cells (MCV).
 Microcytic- small red blood cells MCV <80
 Normocytic- normal sized cells MCV (80-100)
 Macrocytic- large red blood cells MCV > 100
Microcytic anaemia
Often termed iron deficiency anaemia, the bone marrow doesn’t have enough iron to
produce normal sized red blood cells. This is through…
Iron loss:
 Bleeding (worm infection STH, Schistosomiasis)
 Menstruation
 Peptic ulcer disease
Inadequate dietary intake of iron:
 Diet deficient in red meat and legumes
Extra requirements
 Pregnancy/ Lactation
 Growth (puberty)
Provided by T. Whitfield 2012
Treating Iron deficiency anaemia
Ferrous sulphate tablets 200mg od to tds will replace iron stores but cause indigestion and
black stools.
Look to treat any cause praziquantel and albendazole are often given without diagnosis as
hookworms and schistosomiasis are so common. Peptic ulcers should be treated with
protein pump inhibitors (eg omeprazole), if severe surgical opinion should be sought.
Transfusion is appropriate if the anaemia is severe, world wide a Hb less than 8g/dl would
be a candidate for transfusion, in Malawi it usually considered at less than 6g/dl, unless the
patient is having palpitations and feeling weak.
Normocytic anaemia
This is usually due to chronic disease as the bone marrow becomes tired and produces less
red blood cells, in acute bleed normocytic anaemia is also seen.
Common causes of normocytic anaemia
 Renal Failure (decreased erthropoetin production)
 Chronic disease: HIV, TB any other long term condition. (This can also be
microcytic)
 Acute blood loss
Treatment
Treating normocytic anaemia relies on treating the cause, transfusion and iron may be
appropriate.
Macrocytic anaemia
Large cells are formed by the bone marrow due to absence of vitamins.
Causes
 Folate deficiency**
 Vitamin B12 deficiency **
 Alcohol
 Hypothyroidism
**These tend to have an MCV> 120 fL
Provided by T. Whitfield 2012
Notes on B12 and folate deficiency
Vitamin B12 is absorbed in the jejunum using intrinsic factor released from the stomach. B12
anaemia is rarely due to poor dietary intake. Usually there is a problem with this pathway…
 Gastrectomy (no stomach to produce intrinsic factor)
 Pernicious anaemia (antibodies against intrinsic factor, autoimmune disease)
 Malabsorption of intrinsic factor in jejunum (patient has diarrhoea, takes months)
Folate deficiency usually results from a diet absent in green vegetables and fruits deficiency
it can develop within weeks.
Treating Macrocytic anaemia
Folate and B12 anaemia can be diagnosed by testing their levels in the blood. This is not
commonly done in Malawi.
Vitamin B12 is replaced with intramuscular injections 1mg 6 times spaced over 2 weeks
followed by every 6 months afterwards. This avoids needing intrinsic factor.
Folate is replaced with a 5mg od tablet.
Haematocrit notes
Haematocrit looks at the concentration of the blood. A low Hct may indicate dilution of the
blood, if the Hct is low then has the sample come from a drip arm? Has the patient been
onn a large amount of IV fluids?
White cell Count
White cells are used for fighting infections, during an infection they are usually raised.
Different subsets of white cell are raised in different infections…
Neutrophils
These tend to be raised in bacterial infections, but also in burns, pancreatitis and other
physiological stresses.
Lymphocytes
These cells tend to be raised in viral infections, they can also be raised in chronic
lymphocytic leukaemia.
Eosinophils
These cells tend to be raised in helminth infections
Provided by T. Whitfield 2012
Platelets
Platelets are responsible for clotting the blood, they are also often raised in infection. The
platelets can also drop and cause spontaneous bleeding.
Causes for spontaneous drop in platelets and bleeding include disseminated intravascular
coagulation (DIC), Haemolytic Uraemic Syndrome, idiopathic thrombocytopaenic purpura
and Thrombotic Thrombocytopaenia.
For full assessment you would also need coagulation times which are not routinely done in
Malawi. Coagulation disorders with spontaneous bleeding are best managed by giving FFP
and platelets. These therapies are often blind as we cannot measure INR or APPT to see if
they have been corrected.
Provided by T. Whitfield 2012
Cerebro- spinal fluid (CSF)
Cerebrospinal fluid is taken via a lumbar puncture; it is usually done on patients with
confusion or meningism.
CSF is mainly analysed to find which kind of meningitis is present.
The first thing to look at is the colour and pressure of the fluid when CSF is reached in
lumbar puncture (LP).
Bacterial
Appearance
TB
Viral
Cloudy
Clear mostly
Clear
WCC/mm
90-1000+
10-1000
50-1000
Type wcc
Polymorph
Lymphocyte
Lymphocyte
Glucose
<1/2 blood
<1/2 blood
>1/2 plasma
Protein
>1.5
1-5
<1
Organisms
Seen
Rarely seen
Not seen
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Cryptococcal Meningitis
In patients with HIV another common cause for meningitis is cryptosporidium neoformans.
This will give a raised pressure when inserting the needle in.
Results in cryptococcal meningitis
 Clear/ slightly turbid fluid
 Raised lymphocytes
 Protein increased
 Glucose slight decrease
 Staining reveals yeasts
 India ink stain 75% effective if C.neoformans present
Provided by T. Whitfield 2012
Urea and Electrolytes
This measures
Sodium (Na+)
Pottassium (K+)
Bicarbonate (HCO3-)
Urea or Blood Urea Nitrogen (BUN)
Creatinine (Creat)
135-145mmol/L
3.5-5mmol/L
22-28mmol/L (110-140mg/dL)
2.5-6.7mmol/L (7-21mg/dL)
70-150µmol/L (0.6-1.3mg/dL)
Sodium
When interpreting a sodium level you must know the fluid status of a patient.
Questions to ask involve:
Is the patient dehydrated?
Is the patient Oedematous?
Are they on any drugs?
Do they have any other medical problems?
Hyponatraemia
Low sodium can arise in dehydrated, fluid overloaded and normally hydrated patients. Once
you know the cause you can look to appropriate treatment.
Common causes of low sodium in dehydrated patients
 Diarrhoea
 Burns
 Diuretics (frusemide, HTC)
Causes of low sodium in oedematous patients
 Heart failure
 Liver failure
 Renal failure
 Nephrotic syndrome
Rare causes of low sodium in euvolaemic patients
 Syndrome of inappropriate ADH secretion
 Hypothyroidism
Treating Hyponatraemia
If >125 mmol/L it is usually fine to just observe the patients.
Provided by T. Whitfield 2012
Try to correct the underlying cause it is usually inappropriate to give salt or saline as the
patient is not usually salt deplete, unless there is obvious fluid loss then normal saline may
be used.
However if the patient is fitting hypertonic saline can be given to correct the sodium (rarely
done).
The caution of giving sodium is that too fast correction of sodium can cause irreversible
brain damage(by osmotic demyelination in the brain).
In correcting the sodium aim for 10mmol/L per day this can be calculated as one litre of N
saline will raise the concentration by 4-5 mmol/L
Hypernatraemia
Hypernatraemia is most commonly due to dehydration (burns, vomiting etc)
Hypernatraemia can also be caused by…
 Excessive Normal saline
 Too high blood sugar
 After head injury - diabetes insipidus
Treating hypernatraemia
Usually give fluids to correct dehydration.
Pottassium
Hyperkalaemia
There are few symptoms of hyperkalaemia itself with patients often just collapsing with
arrthymias or sudden death. Symptoms may relate to the underlying cause eg.
oliguria/anuria in renal failure.
Hyperkalaemia is common in renal failure where K+ is usually excreted at the expense of Na+
renal failure means an excess of potassium is retained. The potassium sparing diuretic
spironolactone is a common cause of hyperkalaemia. Other causes include acidosis, muscle
cell destruction and burns.
Artefact: high potassium can occur when red blood cells break down inside the collecting
tube if it is unexpected then it should be repeated.
Raised potassium above 6.5 mmol/l can cause life threatening arrthymias, it is treated …
 Calcium gluconate 10% 10ml given iv to prctect the heart
Provided by T. Whitfield 2012
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Insulin 10-20 units in 10% dextrose given over 5hours (the insulin drives the
potassium into the cells
Salbutamol nebulisers 5mg also drive potassium back into the cells.
In severe hyperkalaemia it may be appropriate to dialyse.
Then look to treat the underlying cause.
Hypokalaemia
If the potassium is <2.5mmol/L it can be life threatening symtpoms and complications
include muscle weakness, hypotonia, cramps and arrhythmias.
Common causes of hypokalaemia include vomiting, diarrhoea and other intestinal problems.
The diuretic drug frusemide is also responsible for lowering potassium.
Treating hypokalaemia
Correct the underlying cause and replace the potassium, in severe hypokalaemia
(<2.5mmol/L) replace intravenously slowly at no more than 20 mmol over an hour, any
faster can lead to arrhythmia.
In less severe hypokalaemia oral sando K can be given at 1-2 tablets up to three times a day.
Potassium tablets should not be given for more than 5 days to avoid hyperkalaemia.
Bicarbonate
Bicarbonate measures the acidity of the blood it is low if the blood is acidic and raised in
alkalosis.
Common causes of acidic blood…
 Lactic acidosis (is the patient on ARVs ? metformin?)
 Diabetic ketoacidosis (check the blood sugar)
 Renal failure (urine output)
Acidotic patients should be given lots of fluid to wash out and dilute the acid, the urine
output and fluid status should be monitored whilst doing this to avoid fluid overload, any
causative drugs should be withdrawn.
Urea and Creatinine
Urea and creatinine are markers of renal function. They are raised in acute kidney injury and
in chronic renal failure.
Provided by T. Whitfield 2012
Urea/BUN may also be raised in muscle damage and gastrointestinal bleeding as the blood/
muscle cells are digested it raises the urea levels.
Liver Function Tests (LFTs)
Liver function tests consist of
Billirubin (bil)
Alanine aminotransferase (alt)
Aspartate transaminase (ast)
Alkaline phosphatase (ALP)
Albumin (alb)
3-17 µmol/L
3-35 iu/L (1-1.4 mg/dL)
3-35 iu/L
30-300iu/L
35-50 g/L (3.5-5.5 U/L)
A raised bilirubin is seen as jaundice in the patient. Jaundice is classified as…
 Pre-hepatic
 Intra hepatic
 Post-hepatic
Pre-hepatic jaundice
Pre-hepatic jaundice in adults is usually caused by blood haemolysis and should therefore be
present with anaemia. The patient should not have any disruption to their other liver
enzymes. Urobiligen in the urine and increased reticulocytes on a blood film would be
expected.
Intra-hepatic jaundice
Intra-hepatic jaundice will present with elevation of all liver enzymes, elevated bilirubin and
either low or normal albumin. The ast, alt and alp all be elevated the ast and alt are usually
higher than the alp.
The most common causes of intra-hepatic jaundice are viruses such as Epstein Barr virus
(EBV), Hepatitis A, Hepatitis B, Hepatitis C as well as alcohol, Tuberculosis medications and
malignancy. Usually there is no pain associated with these conditions.
Post-hepatic jaundice
Post hepatic jaundice is caused by obstruction of the billary tree. This causes a back log of
conjugated bilirubin from the bile ducts to the blood.
The liver enzymes will all be elevated as in intra-hepatic jaundice, however in post hepatic
jaundice the alp tends to be greatly elevated above the ast/alt.
Common causes of post hepatic jaundice include gall stones blocking the bile duct,
pancreatic tumour and billary stricture. Gall stones are very painful as opposed to tumours.
Provided by T. Whitfield 2012
In Malawi abdominal ultrasound is used in all jaundice cases to look for correctable
obstructive causes and to look at the texture of the liver.
Albumin
Albumin is a measure of the synthetic function of the liver. In cirrhosis the function of the
liver is poor and albumin will drop. Chronic disease states such as malnutrition, HIV and TB
will also lower the albumin as the liver is compromised.
Provided by T. Whitfield 2012
Analysing urine
This is done through analysing the urine in the lab and urine dipstick on the ward.
Urine dipstick
This measures:
 Blood: shouldn’t be present, positive in UTI, Glomerulonephritis, bladder/renal
tumour, schistosomiasis, trauma (catheter), renal stones
 Leucocytes (White cells): present in infection mainly.
 Ketones: present in starvation at low levels, tends to be greater than ++ in DKA
 Nitrites: the break down product when bacteria digest nitrate, positive in UTI
 Protein: +++ protein by itself with nil else suggests nephrotic syndrome, also can be
present in glomerulonephritis, UTI, exercise and pregnancy. Diabetic renopathy will
have protein in the urine as the disease progresses.
 Bilirubin present on the dipstick indicates obstructive jaundice
 Urobilinogen: indicates pre-hepatic jaundice
 Specific gravity range 1.000- 1.030 indicates the density of the urine and indicates the
degree of protein/ blood in the urine.
Urine microscopy
This looks at the urine under a microscope to see what is in the urine.
Urinalysis measures
 Red cells: which occur for the same reasons as in the dipstick. >2mm3 is abnormal
 White cells: for the same reasons as in the dipstick, but they are counted for
significance. >10/mm3 is abnormal
 Protein: this will state the volume being excreted. Should be <150mg/day, it can be
raised for the same reasons as protein is found on the urine dipstick. Microscopy will
detect lower levels of proteinuria.
Casts are also seen in the urine
Casts are made when the cells/ material bunch together in the glomerulus to form a lump
which is then passed out in the urine. The casts have the shape of the part glomerulus
where they formed.
Hyaline/ granular casts: these occur commonly in individuals who exercise and those taking
loop diuretics. Dense granular casts can occur in diabetic nephropathy and
glomerulonephritis.
Red cell casts: indicate any blood found has come from the glomerulus this happens in
extreme hypertension and glomerulonephritis.
White cell casts: occur in pyelonephritis and some forms of glomerulonephritis.
Provided by T. Whitfield 2012
Fatty casts: in heavy proteinuria
Epithelial cell casts: in acute tubular necrosis or glomerulonephritis.
Pleural Fluid analysis
These are classified according to their protein content as either transudates (<30g/L)or
exudates (>30g/L).
Transudates are commonly due to…
 Increased venous pressure,
 Hypoproteinaemia (low oncotic pressure)
 Cardiac failure
 Cirrhosis
 Pericarditis
 Nephrotic syndrome
 Fluid overload
 Malabsorption
 Ascitic fluid analysis
 Malnutrition
A transudate may also be related to ovarian cancer (right sided effusion in Meigs syndrome)
and in hypothyroidism.
Exudates are commonly due to…
 Pneumonia
 Malignancy (lymphoma, Kaposi sarcoma, others)
 TB
 Blood in the pleural cavity suggests malignancy, trauma or TB.
 If lymphocytes are the dominant white cell Tb is also suggested.
Provided by T. Whitfield 2012
Ascitic fluid analysis
Ascitic fluid looks at white cell count greater than 200 suggests bacterial peritonitis. If these
are mainly lymphocytes then it could be TB peritonitis.
Culture is performed to determine the organism.
Protein levels are greater than 30 g/L in the following conditions
 Malignancy
 TB
 Bacterial infection
 Pancreatitis
Protein levels are less than 30g/L in the following conditions
 Congestive cardiac failure
 Nephrotic syndrome
 Cirrhosis
 Myxoedema
 Portal vein thrombosis
Diuretic therapy can increase protein levels in the ascitic fluid in conditions where it would
normally be <30g/L.
Bloody ascites is usually due to malignancy and occasionally TB.
Provided by T. Whitfield 2012