Saturday, April 16, 2016


I. Introduction

Sodium is the most abundant cation in the extra cellular fluid (ECF), represented 90% of all extracellular cation and largely determines the osmolality of the plasma. Active transport system at the cellular membrane maintain high Na+ levels in the ECF, where as K+ is concentrated with in the cell. 
Changes in extracellular Na+ concentration result in increase or decreases in the osmolality of the ECF, which in turn, influence the distribution of body water. It is therefore related in regulation of water balance as well as blood volume in the body.

Normally, serum Na+ concentration varies between 136 and 145 mmol/L in healthy individuals. The normal daily intake of Na+ is 100-250 mmol. Ordinarily, the amount of Na+ loss is balance by the daily intake.

Determination of Na+ level is of vital key in the proper diagnosis and treatment of diseases associated with it. 

A decrease in serum sodium level, termed as “hyponatremia” is usually seen in hypoadrenalism, potassium deficiency, diuretic use, ketonuria, salt-losing nephropathy, prolonged vomiting, diarrhea, renal failure, hepatic cirrhosis, congestion heart failure (CHF) and diabetic ketoacidosis. 

Whereas, an increase in serum sodium level, termed as “hypernatremia” is seen in profuse sweating, severe burns, dehydration, malnutririon, edema, ascitis in chronic failure, uncontrolled diabetes, and nephritic syndrome.

II. Procedure/ Flowchart of the experiment
Pipet out 0.1ml serum and place in a test tube
Add 3ml base reagent followed by 3 drops of color reagent
Mix thoroughly for 30sec. and let it stand for 30min. at room temperature
Read at 550nm against a water blank
Interpret results obtained


Place 0.1 ml of unhemolyzed serum into 16X100 mm test tubes.

Label tube as test serum standard.

Add 2.5 ml of Sodium Base Reagent into the tubes.

Place 3 gtt of Sodium Color Reagent.

Mix well and read at 550 nm against a water blank.

III. Results and Discussion

Concentration of the unknown: 531.62 mmol/L
Normal range for serum specimen: 134-148 mmol/L
Interpretation: “Above normal range”

The interpretation of the result obtained was above normal range because it exceeds the maximum Na+ level that a normal adult could have.

IV. Intrinsic and Extrinsic factors

The probable sources of errors are:
-          contaminated tubes or cuvets
-          contaminated serum
-          ineffective reagent
-          under/ over centrifugation
-          prolonged standing of specimen
-          misreading of result by spectrophotometer

Tuesday, August 11, 2015

Chemical Structure of Seawater

Seawater differs in chemical structure from plain water because of additional components that are present.  Just by tasting, you would know that seawater is briny and contains salts that are not found in your ordinary drinking water. What is the chemical structure of seawater that makes it different?

1. Seawater has salts

Seawater has an average salt content of approximately 35 grams for every    liter of seawater or 3.5% salt content.  The salt includes calcium (Ca++), potassium (K+), chloride (Cl-), sodium (Na+), sulfate (SO4++), and magnesium (Mg++).

Sodium and chloride constitute majority of the seawater salts.
This chemical structure allows salinity of seawater. The salinity of seawater is constant and measuring one major salt allows representation of the other concentrations.

2. Seawater is denser than fresh water

The density of pure water is 1.00 grams per milliliter at specified temperatures. Seawater is denser, which is 1.025 grams per milliliter. The salt content of seawater makes it denser.

3. Seawater has a pH of 7.5 to 8.4

Pure water has a neutral pH at 7, but seawater
is more alkaline with pH range of 7.5 to 8.4. This is due to the presence of additional chemical components not found in fresh water.

4. Seawater has traces of other chemicals

Aside from the salts mentioned, seawater also has smaller amounts of strontium (Sr), bicarbonate (HCO3), bromide (Br), borate (BO3), and fluoride (F). There are still various chemicals present in sea water depending on its location and depth.

The aforementioned chemical structure of seawater enables measurement of distances based on sound which travels through the seawater’s components. These chemical components make seawater different from fresh water, pure water or river water.

The chemical components and salinity of water also prevents it from becoming potable or drinkable. The salt content of seawater could aggravate an existing condition of hypertension and cardiovascular conditions because the increased concentration of salt in the blood will influence the amount of water inside the cell.

The increase of sodium will promote osmosis, which will eventually drain the cells of water. The dehydration of the cells can cause heart conditions like arrhythmia.

It is great to know the seawater’s chemical structure so that you will know why seawater is not advisable to drink and to hydrate the body with. Knowing this basic fact would also allow you to keep abreast of simple scientific information that are essential for your health and well-being.

Sunday, July 26, 2015

Renal Function Test: BUA, BUN and Creatinine


            The major function of the kidneys is to eliminate waste products from the body and reabsorbed the substances essential for body function. When the kidneys’ functions are impaired, one or both processes are altered. 

Image credit:

Measurements of the ability of the kidneys to carry out their major processes provide vital data in knowing whether they’re normally functioning or not.
            To know whether a kidney functions correctly we may perform different tests such as, test for Blood Urea Nitrogen (BUN), Creatinine and Blood Uric Acid (BUA).


            Creatinine is used to diagnose impaired renal function.

            This test measures the amount of creatinine in the blood. Creatinine is a catabolic product of creatinine phosphate, which is used in skeletal muscle contraction. 

The daily production of creatine and subsequently creatinine depends on muscle mass, which fluctuates very little. 

Creatinine, as BUN, is excreted entirely by kidneys and therefore is directly proportional to renal excretory function. Thus, with normal renal excretory function, the serum creatinine level should remain constant and normal. 

Only renal disorders such as glomerulonephritis, pyelonephritis, acute tubular necrosis, and urinary obstruction, will cause an abnormal elevation in creatinine. 

There are slight increases in creatinine levels after meals, especially after ingestion of large quantities of meat. Furthermore, there may be some diurnal variation in cr.
            The serum creatinine test, as with the BUN, is used to diagnose impaired renal function. Unlike BUN, however, the creatinine level is affected minimally by hepatic function. 

The serum creatinine level has much the same significance as the BUN level but tends to rise later. Therefore elevations in creatinine suggest chronicity of the disease process. 

In general, a doubling of creatinine suggests a 50% reduction in the glomerular filtration rate. The creatinine level is interpreted in conjunction with the BUN.


v  ELDERLY         decrease in muscle mass may cause decreased values
FEMALE        0.5-1.1 mg/dL or 44-97 umol/L
MALE             0.6-1.2 mg/dL or 53-106 umol/L
v  ADOLECENT                        0.5-1.0 mg/dL
v  CHILD                       0.3-0.7 mg/dL
v  INFANT                     0.2-0.2 mg/dL
v  NEWBORN               0.3-1.2 mg/dL


v  A high diet in meat content can cause transient elevations of serum creatinine.
v  Drugs may increase creatinine values include aminoglycoside (e.g. gentamicin), cimetidine, heavy-metal chemotherapeutic agents (e.g. cisplatin), and other nephrotoxic drugs such as cephalosporins (e.g. cefoxitin)



Disease affecting renal function, such as glomerulonephritis, pyelonephritis, acute     tubular necrosis, urinary tract obstruction, renal blood flow (e.g. shock, dehydration, congestive heart failure, atherosclerosis), diabetic nephropathy, nephritis. With these illnesses, renal function is impaired and creatinine levels rise.

Rhabdomyolysis. Injury of the skeletal muscle causes myoglobin to be released in the blood stream. Large amounts are nephrotoxic. Creatinine levels rise.

These diseases are associated with increased muscle mass, which causes the “normal” creatinine level to be high


Decreased muscle mass (e.g. muscular dystrophy, myasthenia gravis)
The diseases are associated with decreased muscle mass, which causes “normal” creatinine level to be low.

Saturday, July 18, 2015

Potassium, the Major Intracellular Cation

Potassium is the primary intracellular cation. It is also an integral part of the transmission of nerve impulses.  It participates in the sodium-potassium pump in the body. 

Unhemolyzed serum should be used because hemolysis will markedly increase the potassium values because potassium is present in large amounts inside the cell.

Clinical Significance

1.      Hyperkalemia – increased concentration of potassium in the bloodstream. It’s found in the following conditions:

         Decreased renal excretion

         Acute or chronic renal failure
         Addison’s disease

·         Cellular shift

         Muscle/cellular injury

Increased intake

             Oral or IV potassium replacement therapy

-          Artifactual

                        Sample hemolysis
                        Prolonged tourniquet use of excessive fist clenching

2.      Hypokalemia – decreased concentration of potassium in the blood stream, seen in the following conditions:

            GI loss

                        - Vomiting
                        - Diarrhea
                        - Gastric suction
                        - Intestinal tumor
                        - Malabsorption
                        - Cancer therapy
                        - Large doses of laxatives

          Normal values:

                           K = 3.5-5.3

         Plasma and serum: 3.4 – 5.0 mmol/L
         Urine: 25 -125 mmol/L

Wednesday, June 24, 2015

Outline of Methamphetamine


 Class of drugs is sympathomimetic

 Has direct stimulant activity on the CNS and Myocardium

 It is widely used to treat obesity

 They are extensively abused by individuals who try to stay awake for long period of time

 the effects of Methamphetamine generally last 2-4 hours

 has a half-life of 9-24 hours in the body

 generally detectable in the urine for 3-5 days

 Confirmatory testing is performed using GCMS.

 the effects of Methamphetamine generally last 2-4 hours

 has a half-life of 9-24 hours in the body

 generally detectable in the urine for 3-5 days

 Confirmatory testing is performed using GCMS.

Screening Sample – Urine
Confirmatory Sample - Blood


1. Immunoassay Systems Screening procedure (Methamphetamine card test)

2. Liquid or gas chromatography


-Adulterants, such as bleach or other strong oxidizing agents.

- Clean container w/o any preservatives

- Store the urine specimen at 2-8 degrees C or freeze urine specimen (-20degrees C) for longer storage

Friday, June 19, 2015

Solving the weight of substances needed to produce molar and normal solutions

To be able to solve the weight of substances needed to prepare certain molar and normal solutions, you can use the general formulas:

For Normal solutions

N = GEW/L of solution

GEW = W/MW/v

N = (W/MW/v)/L of solution


GEW = Gram Equivalent Weight

L = Liter

W = weight in grams of substance

EW = Equivalent Weight

MW = Molecular Weight

v = valence

The short cut formula is:

W = DN X DV X EW (MW/v)


DN = Desired Normality
DV = Desired Volume
EW = Equivalent Weight
MW = Molecular weight
v = valence

Here’s a sample problem.

How much CaCl2 will you need in preparing 500 mL of a 0.5 N solution?
W = DN X DV X EW (MW/v)
W = 0.5 X 0.5 X (111/2)
W = 13.875 grams of CaCl2

To prepare the 0.5 N CaCl2 solution:

Weigh 13.875 grams of CaCl2 and dilute it to 500 mL of solution in  a volumetric flask. You can first dispense 250 ml of the distilled water to the flask, dissolve the 13.875 CaCl2, and then add the diluent up to the 500 mL mark of the volumetric flask.

Take note of the following:

1.    Volume must always be converted to liters when using this formula, or if you don’t want to convert, divide your answer by 1,000.

2.    The powder must not be added to 500 ml or 0.5 L but diluted TO 500 mL to in a volumetric flask to get the exact volume. The resulting volume in your 500 ml flask after dissolving the CacL2 must not be more or less than 500 ml. This will ensure accuracy of your measured solution.

For Molar solutions

M = GMW/L of solution

GMW = Weight/MW

M = (W/MW)/L of solution


GMW = Gram Molecular Weight

L = Liter

W = weight in grams of substance

MW = Molecular Weight

v = valence

Hence for Molar solutions the formula is:



DM = Desired Molarity
DV = Desired Volume
MW= Molecular Weight

If you're given the same data but asked to solve for the molarity this is the formula and substitution:

Here’s a sample problem.

How much CaCl2 will you need in preparing 500 mL of a 0.5 M solution?
W = 0.5 X 0.5 X 111
W = 27.75 grams of CaCl2
The only difference from the Normal solution is the absence of valence. 

To prepare the 0.5 M CaCl2 solution:

Weigh 27.75 grams of CaCl2 and dilute it to 500 mL of solution in  a volumetric flask. 
You can first dispense 250 ml of the distilled water in the flask, dissolve the 27.75 CaCl2, and then add the diluent up to the 500 mL mark of the volumetric flask.