Adults 3.5–5.3 mEq/L 3.5–5.3 mmol/L
Premature infants 5.0–10.2 mEq/L 5.0–10.2 mmol/L
Cord blood 5.0–10.2 mEq/L 5.0–10.2 mmol/L
2 days 3.0–6.0 mEq/L 3.0–6.0 mmol/L
Cord blood 5.6–12.0 mEq/L 5.6–12.0 mmol/L
Newborn 3.7–5.0 mEq/L 3.7–5.0 mmol/L
Infants 4.1–5.3 mEq/L 4.1–5.3 mmol/L
Children 3.4–4.7 mEq/L 3.4–4.7 mmol/L
Adults < 2.5 mEq/L < 2.5 mmol/L
or > 6.6 mEq/L or > 6.6 mmol/L
Newborn < 2.5 mEq/L < 2.5 mmol/L
or > 8.1 mEq/L or > 8.1 mmol/L
Adults 136–145 mEq/L 136–145 mmol/L
Umbilical cord 116–166 mEq/L 116–166 mmol/L
Infants 139–146 mEq/L 139–146 mmol/L
Children 138–145 mEq/L 138–145 mmol/L
Alterations of Sodium and Extracellular Fluid (ECF)
Hyponatremia (Serum Sodium Concentration Lower
Total-body sodium and ECF volume low:
¾ “Third compartment” accumulation
Total body sodium and ECF volume normal
¾ Acute water intoxication, usually iatrogenic
¾ Syndrome of inappropriate ADH secretion.
¾ Severe whole body potassium depletion.
Total body sodium and ECF volume increased
¾ Acute renal failure with superimposed water load
Hypernatremia (serum sodium concentration higher
Total body sodium normal, ECF volume low
Total body sodium increased proportionately more than
¾ Salt ingestion, deliberate or accidental.
¾ Inappropriate intravenous therapy.
Hyperosmolality, without sodium alterations
¾ Radiographic contrast media.
Abnormalities of Serum and Whole Body Potassium
Hyperkalemia (serum potassium concentration more
Inappropriate cellular metabolism
¾ Cell necrosis (burns, crush, hemolysis, anti-leukemia
¾ Chronic interstitial nephritis
¾ Tubular unresponsiveness to aldosterone
FIG. 21.4: Standard air compressor for flame photometers
Blood Gases and Electrolytes 561
FIG. 21.5: Bayer 614 electrolyte analyzer
• 20 character alphanumeric vacuum fluorescent display
• Caliberation and slope solutions are contained within instrument
• Stable: the measured calibration value will change by less than
+/– 2 mmol/L na+ and +/– 0.1 mmol/L K+ in a 1 hour period at
Specifications 614 634 644 654 664
ISE ISE ISE ISE ISE, thermal cond
¾ Inappropriate use of salt substitutes or K+ replacement.
¾ Potassium salts of antibiotics.
Hypokalemia (serum potassium concentration lower
Inappropriate cellular metabolism
¾ Very rapid generation of cells (leukemia, treated
¾ Diet deficient in vegetables, meat
¾ Clay eating (binds potassium and prevents absorption).
RAPID DIAGNOSTICS IN ELECTROLYTE ANALYSIS
Within a remarkably short period of only a few years,
a variety of analyzers have appeared in the market
which use ion-selective electrodes (ISE) for quantitative
measurements of biologically relevant cations and anions.
The electrode (ISE) permits measurement of the activity of
a specific ion under the presence of a given amount of other
ions. The selective transport of a certain ion species from
the solution into the membrane phase of the electrode
allows a potential difference that can be calculated and the
ion concentration can be deduced thereof.
Ion selective electrodes are available for H+ (for pH
measurement), Li+ (Lithium), Na+, K+, Ca++ and Cl¯.
Bayer 614 Na+ K+ Electrolyte Analyzer (Fig. 21.5)
The Corning 614 is designed for whole blood, plasma—
using lithium heparin as anti-coagulant. Fresh samples
can be analyzed at temperatures up to 40°C.
Serum may be used (free from hemolysis) within a
Urine may be used, diluted 1 part sample to 9 parts
urine diluents as long as samples are not collected into
Sample presentation may be syringe, blood collection
tube, centrifuge tube, vial, vacutainer, etc. A sample
measurement result will be displayed within 35 seconds of
pressing analyze blood? or analyze urine? button. Sample
to sample measurement result will be displayed within
35 seconds of pressing analyze blood? Or analyze urine?
Button. Sample to sample measurement time is 60 seconds.
Whole blood, serum, plasma, and QC material)
Analysis time 35 seconds Within 60 Sec 35 seconds 40 seconds 35 seconds,
Na+ 80–200 mmol/L N/A 80–200 mmol/L 80–200 mmol/L 50–200 mmol/L
(Urine) 10–350 mmol/L N/A 10–350 mmol/L 10–350 mmol/L 10–350 mmol/L
K+ 0.5–9.99 mmol/L N/A 0.5–9.99 mmol/L 0.5–9.99 mmol/L 0.5–20 mmol/L
(Urine) 5–250 mmol/L N/A 5–250 mmol/L 5–250 mmol/L 5–300 mmol/L
Cl– N/A N/A 50–200 mmol/L N/A 20–200 mmol/L
(Urine) N/A N/A 10–350 mmol/L N/A 15–400 mmol/L
tCO2 N/A N/A N/A N/A 3–60 mmol/L
Ca++ N/A 0.2–5.0 mmol/L N/A N/A N/A
pH N/A 6.50–8.00 mmol/pH N/A N/A N/A
Li+ N/A N/A N/A 0.2–0.50 mmol/L N/A
Weight 14 lbs 14 lbs 14 lbs 14 lbs 64 lbs
The immune system offers protection against invading
microorganisms, viruses and other foreign materials.
Somehow, it must distinguish between Valuable what
“belongs” and what doesn’t “belong”. Failure to detect
and expel foreign materials can lead to problems due to
immunodeficiency (i.e. AIDS) and misidentification of
Antigen is a molecule that binds with an antibody or T
cell receptor (antigenicity is the ability to bind to the
Immunogen is a molecule that can elicit an immune
response (immunogenicity is the ability to elicit an
Several factors influence how “antigenic” a molecule is.
Most important is how foreign it is, with molecules that
are most unlike self-being the most antigenic. There are
also numbers of physical and chemical determinants,
which also matter molecular size — the larger the better,
generally. 1000 Daltons are about the lower limit.
¾ Complexity: The more complex the better. For example,
simple repeating polysaccharides like starch aren’t
very good, while proteins with a constantly changing
sequence of 20 or so different amino acids are good
¾ Structural stability: A fixed shape is helpful. For
example, gelatin (which wobbles) is a poor antigen
For a molecule such as a protein, a given antibody will
“be directly against” only one of all the possible parts of
the entire molecule. This part is known as an EPITOPE.
A molecule may have several epitopes. Also, a complex
antigen (such as a cell) will have many molecules, each of
which will contain several epitopes.
An epitope is also known as an antigenic determinant.
Some epitopes are better able to elicit antibodies than
others. They are known as Immunodominant Epitopes.
About 6 units of a polysaccharide chain, or about 6–8 amino
acids. For a protein epitope, it is the shape of the epitope,
rather than the specific amino acid sequence that is
FIG. 22.1: Sites for obtaining blood by venipuncture from forearm
564 Concise Book of Medical Laboratory Technology: Methods and Interpretations
important. For example, a few amino acids, which come
from different parts of the chain, can come together in one
physical spot to create an epitope.
When an antibody directed against one epitope can
bind to another epitope, this is known as “cross-reactivity”.
If this happens, it will be because the two epitopes ‘look
Some intestinal bacteria possess antigens that look
like blood group A and B antigens which can be absorbed
through the intestinal wall into the bloodstream; therefore,
people of blood group A will have antibodies against the B
antigens even if they never have been exposed to B-type
and spider monkeys to an increasingly lesser extent.
What are the Different Kinds of Epitopes?
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