MLS Clinical Chemistry: Comprehensive Review Vocabulary

Vocabulary practice flashcards covering proteins, SPEP patterns, electrolytes, osmolality, blood gas parameters, and clinical calculations for medical laboratory science.

Anion Gap

A calculated value defined as $\text{AG} = \text{Na}^+ - (\text{Cl}^- + \text{HCO}_3^-)$ used to screen for unmeasured anions, where an increased gap supports organic acidosis.

Calculated Osmolality

An estimate of serum osmolality derived from routine chemistry values using the formula $2 \times \text{Na}^+ + \frac{\text{glucose}}{18} + \frac{\text{BUN}}{2.8}$.

Osmolal Gap

The difference calculated as $\text{Measured osmo} - \text{calculated osmo}$, where an increased gap suggests unmeasured osmoles or pseudohyponatremia issues.

Corrected Sodium

An estimated sodium value after hyperglycemia-related water shift calculated as $\text{Na}^+ + 1.6 \times \left[\frac{\text{glucose} - 100}{100}\right]$.

Henderson–Hasselbalch Equation

The acid–base formula $\text{pH} = 6.1 + \log\left(\frac{\text{HCO}_3^-}{0.0306 \times \text{PaCO}_2}\right)$ connecting metabolic and respiratory components of blood pH.

Isoelectric Point (pI)

The pH at which an amino acid or protein carries a net charge of zero as a zwitterion and electrophoretic migration stops.

Zwitterion

A dipolar form of an amino acid near physiologic pH where equal positive and negative charges yield a net charge of zero.

Primary Structure

The specific sequence of amino acids in a polypeptide chain, stabilized primarily by covalent peptide bonds.

Secondary Structure

Local folding patterns of a polypeptide backbone including $\alpha$-helices, $\beta$-sheets, and random coils, stabilized by hydrogen bonds in the backbone.

Tertiary Structure

The overall 3D shape of a single polypeptide, stabilized by side-chain interactions such as hydrophobic effects, ionic bonds, hydrogen bonds, Van der Waals forces, and disulfide bonds.

Quaternary Structure

The spatial arrangement and combination of multiple polypeptide subunits held together by side-chain interactions between subunits.

Protein Denaturation

The loss of higher-order protein structure and function, commonly caused by heat, pH extremes, detergents, or organic solvents, while primary structure usually remains intact.

Biuret Method

A routine total protein assay principle where peptide bonds form a complex with cupric ions (copper) in an alkaline solution.

Refractometry

A rapid estimation method for protein concentration based on how dissolved protein alters the refractive index of a fluid.

Nephelometry

An analytical method that measures light scatter at an angle, providing high sensitivity for immunoglobulins and specific proteins.

Acute Phase Reaction (SPEP Pattern)

A serum protein electrophoresis pattern characterized by an increase in both $\alpha_1$ and $\alpha_2$ regions during acute inflammation.

Nephrotic Syndrome (SPEP Pattern)

A serum protein electrophoresis pattern demonstrating decreased albumin, elevated $\alpha_2$-macroglobulin, and often decreased $\gamma$-globulins due to selective urinary loss.

Cirrhosis (SPEP Pattern)

A serum protein electrophoresis pattern displaying decreased albumin together with $\beta-\gamma$ bridging caused by polyclonal IgA expansion.

Monoclonal Gammopathy

A serum protein electrophoresis pattern defined by a sharp M-spike, typically in the $\gamma$ or $\beta$ region, caused by clonal immunoglobulin production.

Polyclonal Gammopathy

A serum protein electrophoresis pattern showing a broad increase across the $\gamma$ region, indicating reactive or inflammatory immunoglobulin expansion.

Prealbumin (Transthyretin)

A liver-synthesized protein that transports thyroid hormone and vitamin A; its short half-life makes it useful for monitoring nutrition trends, though it decreases during inflammation.

Positive Acute Phase Reactants

Inflammatory proteins whose serum concentrations increase during inflammation, including CRP, haptoglobin, ferritin, fibrinogen, complement, $\alpha_1$-antitrypsin, and ceruloplasmin.

Negative Acute Phase Reactants

Serum proteins whose hepatic synthesis decreases during inflammation, including albumin, prealbumin, and transferrin.

Direct ISE

An ion-selective electrode method that measures activity in an undiluted sample, making it largely immune to the electrolyte exclusion effect.

Indirect ISE

An ion-selective electrode method that dilutes the sample before measurement; vulnerable to pseudohyponatremia when plasma water fraction is decreased by high lipids or proteins.

Pseudohyponatremia

An artifactually low sodium measurement produced by indirect ISE in samples with severe lipemia or hyperproteinemia due to the electrolyte exclusion effect.

Ionized Calcium ($\text{Ca}^{2+}$)

The free, unbound fraction of calcium that comprises approximately 50% of total calcium and represents the biologically active form.

Colligative Properties

Physical properties of solutions that depend solely on the total number of dissolved particles per volume rather than their molecular identity.

Co-oximetry

A multi-wavelength spectrophotometric method used to directly measure individual hemoglobin species, including oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin.

P50

The partial pressure of oxygen ($\text{PO}_2$) at which hemoglobin is 50% saturated, serving as a measure of hemoglobin-oxygen affinity.

Anion Gap

A calculated value defined as $\text{AG} = \text{Na}^+ - (\text{Cl}^- + \text{HCO}_3^-)$ used to screen for unmeasured anions, where an increased gap supports organic acidosis.

Calculated Osmolality

An estimate of serum osmolality derived from routine chemistry values using the formula $2 \times \text{Na}^+ + \frac{\text{glucose}}{18} + \frac{\text{BUN}}{2.8}$.

Osmolal Gap

The difference calculated as $\text{Measured osmo} - \text{calculated osmo}$, where an increased gap suggests unmeasured osmoles or pseudohyponatremia issues.

Corrected Sodium

An estimated sodium value after hyperglycemia-related water shift calculated as $\text{Na}^+ + 1.6 \times \left[\frac{\text{glucose} - 100}{100}\right]$.

Henderson–Hasselbalch Equation

The acid–base formula $\text{pH} = 6.1 + \log\left(\frac{\text{HCO}<em>3^-}{0.0306 \times \text{PaCO}</em>2}\right)$ connecting metabolic and respiratory components of blood pH.

Isoelectric Point (pI)

The pH at which an amino acid or protein carries a net charge of zero as a zwitterion and electrophoretic migration stops.

Zwitterion

A dipolar form of an amino acid near physiologic pH where equal positive and negative charges yield a net charge of zero.

Primary Structure

The specific sequence of amino acids in a polypeptide chain, stabilized primarily by covalent peptide bonds.

Secondary Structure

Local folding patterns of a polypeptide backbone including $\alpha$-helices, $\beta$-sheets, and random coils, stabilized by hydrogen bonds in the backbone.

Tertiary Structure

The overall 3D shape of a single polypeptide, stabilized by side-chain interactions such as hydrophobic effects, ionic bonds, hydrogen bonds, Van der Waals forces, and disulfide bonds.

Quaternary Structure

The spatial arrangement and combination of multiple polypeptide subunits held together by side-chain interactions between subunits.

Protein Denaturation

The loss of higher-order protein structure and function, commonly caused by heat, pH extremes, detergents, or organic solvents, while primary structure usually remains intact.

Biuret Method

A routine total protein assay principle where peptide bonds form a complex with cupric ions (copper) in an alkaline solution.

Refractometry

A rapid estimation method for protein concentration based on how dissolved protein alters the refractive index of a fluid.

Nephelometry

An analytical method that measures light scatter at an angle, providing high sensitivity for immunoglobulins and specific proteins.

Acute Phase Reaction (SPEP Pattern)

A serum protein electrophoresis pattern characterized by an increase in both $\alpha<em>1$ and $\alpha</em>2$ regions during acute inflammation.

Nephrotic Syndrome (SPEP Pattern)

A serum protein electrophoresis pattern demonstrating decreased albumin, elevated $\alpha_2$-macroglobulin, and often decreased $\gamma$-globulins due to selective urinary loss.

Cirrhosis (SPEP Pattern)

A serum protein electrophoresis pattern displaying decreased albumin together with $\beta\text{--}\gamma$ bridging caused by polyclonal IgA expansion.

Monoclonal Gammopathy

A serum protein electrophoresis pattern defined by a sharp M-spike, typically in the $\gamma$ or $\beta$ region, caused by clonal immunoglobulin production.

Polyclonal Gammopathy

A serum protein electrophoresis pattern showing a broad increase across the $\gamma$ region, indicating reactive or inflammatory immunoglobulin expansion.

Prealbumin (Transthyretin)

A liver-synthesized protein that transports thyroid hormone and vitamin A; its short half-life makes it useful for monitoring nutrition trends, though it decreases during inflammation.

Positive Acute Phase Reactants

Inflammatory proteins whose serum concentrations increase during inflammation, including CRP, haptoglobin, ferritin, fibrinogen, complement, $\alpha_1$-antitrypsin, and ceruloplasmin.

Negative Acute Phase Reactants

Serum proteins whose hepatic synthesis decreases during inflammation, including albumin, prealbumin, and transferrin.

Direct ISE

An ion-selective electrode method that measures activity in an undiluted sample, making it largely immune to the electrolyte exclusion effect.

Indirect ISE

An ion-selective electrode method that dilutes the sample before measurement; vulnerable to pseudohyponatremia when plasma water fraction is decreased by high lipids or proteins.

Pseudohyponatremia

An artifactually low sodium measurement produced by indirect ISE in samples with severe lipemia or hyperproteinemia due to the electrolyte exclusion effect.

Ionized Calcium ($\text{Ca}^{2+}$)

The free, unbound fraction of calcium that comprises approximately 50% of total calcium and represents the biologically active form.

Colligative Properties

Physical properties of solutions that depend solely on the total number of dissolved particles per volume rather than their molecular identity.

Co-oximetry

A multi-wavelength spectrophotometric method used to directly measure individual hemoglobin species, including oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin.

P50

The partial pressure of oxygen ($\text{PO}_2$) at which hemoglobin is 50% saturated, serving as a measure of hemoglobin-oxygen affinity.

Serum Sodium Reference Range

The normal adult concentration range for serum or plasma sodium, which is $135\text{--}145\,\text{mmol/L}$.

Serum Potassium Reference Range

The normal adult concentration range for serum potassium, which is $3.5\text{--}5.1\,\text{mmol/L}$.

Serum Chloride Reference Range

The normal adult concentration range for serum chloride, which is $98\text{--}107\,\text{mmol/L}$.

Serum Bicarbonate Reference Range

The normal concentration range for serum bicarbonate (total $\text{CO}_2$), which is $22\text{--}28\,\text{mmol/L}$.

Total Serum Calcium Reference Range

The typical adult reference interval for total serum calcium, which is $8.6\text{--}10.3\,\text{mg/dL}$.

Albumin to Globulin (A/G) Ratio Reference Range

The normal reference range for the calculated ratio of albumin to globulin in serum, which is $0.8\text{--}2.2$.

Anion Gap Reference Range

The typical reference interval for the calculated serum anion gap, which is $6\text{--}14\,\text{mmol/L}$.

Serum Osmolality Reference Range

The reference interval for normal serum or plasma osmolality, which is $275\text{--}300\,\text{mOsm/kg}$.