BLOOD UREA NITROGEN

BLOOD UREA NITROGEN - serum

Application: Investigation of renal function.

 
Explanation:  In the liver, amino acids (from protein digestion) are catabolized and ammonia is formed.  The ammonia is combined to form urea, which is transported to the kidneys for excretion.  BUN is directly related to the metabolic function of the liver and the excretory function of the kidney. 
   

Increased levels are seen with reduced glomerular filtration due to renal or pre-renal disease; bleeding into the gastrointestinal tract; hypercatabolic states. Reduced values are seen in pregnancy; with water retention; with reduced synthesis as a result of decreased protein intake, severe liver disease, or urea-cycle defects.
   

Patients with increased BUN are said to have azotemia.

Specimen: 5 ml blood in red- or green-top tube.


Reference Interval:

Neonate:
1.0-4.0 mEq/L
Adult:
3.0-8.0 mEq/L

BICARBONATE

BICARBONATE - serum

Application: Acid-base disorders; particularly as initial investigation of metabolic abnormalities.

 

Explanation: Bicarbonate(HCO3-) is quantitatively the second most important anionic fraction in serum. CO2 produced by cellular metabolism diffuses into the plasma and combines with H2O inside red cells to form H2CO3 (carbonic acid). Carbonic acid dissociates to form H+ and (HCO3-). The H+ is buffered by reduced hemoglobin and as the bicarbonate concentration builds up in the red cells, it diffuses down its concentration gradient into the plasma, being replaced by Cl-. This movement of Cl- into the red cell to conserve electrical balance is called the "chloride shift". A small amount of CO2 is also carried in the blood bound to amino groups of hemoglobin. Clinically, bicarbonate and other forms of carbon dioxide are measured together as total CO2.
   

Serum bicarbonate is increased in metabolic alkalosis and in compensated respiratory acidosis. Levels are decreased in metabolic acidosis.


Specimen: 5 ml blood in red- or green-top tube.


Reference Interval:
22-32 mEq/L.

Burkholderia pseudomallei Serology

Negative

Brucella Agglutination

Titre < 20

Bordetella pertussis Culture and Sensitivity

No growth of Bordetella spp.

Bordetella pertussis by Immunofluorescence

Negative

Blood, Aerobic Culture and Sensitivity

No growth

Blood, Aerobic & Anaerobic Culture Sensitivity

No growth

Blood Gases, Arterial

PH: 7.35-7.45

pCO2: 35-45mmHg

pO2: 75-100mmHg

Calc Bicarbonate: 23-33mmol/L 

Std Biicarbonate: 21-27mmol/L

Base Excess: ±2mmol/L

O2 Saturation: 96-100%

Blood Culture, Fungus

No growth of fungus

Bilirubin, Unconjugated

5 - 25 umol/L

Bilirubin, Total

5 - 30 umol/L

Bilirubin, Paediatric

Full Term Baby
0 - 1 day: 34-103umol/L
1 - 2 days: 103-120umol/L
2 - 5 days: 68-103umol/L
5 - 127 days: 5-30umol/L
Premature
0 - 1 day: 17-103umol/L
1 - 2 days: 103-137umol/L
3 - 5 days: 171-205uimol/L

Bilirubin, Direct

0 - 3 umol/L

Bilirubin, Delta

0 - 3 umol/L

Bilirubin, Conjugated

0 - 5 umol/L

Beta-2-Microglobulin

Serum    0 - 1900 ug/L
Urine      0 - 125 ug/L

Bence Jones Protein (BJP)

Negative