Math EQs for MLT exam

% Transferrin saturation and TIBC

% Transferrin saturation = Serum iron/TIBC x100

TIBC= serum transferrin (mg/dL) x 1.25

Unconjugated/indirect bilirubin

Total bilirubin= direct conjugated bilirubin + indirect unconjugated bilirubin

LDL/Friedewald equation/non-HDL

Calculated LDL= total cholesterol – (HDL+TG/5)

TG/5=VLDL

not valid is TG >400mg/dl

Creatinine Clearance

C= (UxV)/P

U= urine level mg/dL

V= urine volume mL/min

P= plasma level mg/dL

Corrected= Clearance (mL/min) x (1.73/A)

 A= body surface area (m²)

                  Remember: 24 hours = 1440 min

Beer’s Law

A= log(100/%T)

A=2-log%T

A= a x b x c

Corrected WBC counts when > 10 nRBCs present

Corrected WBC= (uncorrected WBC x 100)/ (100+# of NRBC per 100 WBC)

Hemacytometer calculations formula

cells/mm3 or cells/mL = (number of cells counted) x (dilution factor) x (volume correction factor)

RBC Hemacytometer

dilution factor: 200

vol correction: 50

units: x10^6 RBC/uL or x10^12 RBC/L

cells/mm3 or cells/mL = (number of cells counted) x (dilution factor) x (volume correction factor)

WBC hemacytometer

dilution factor: 100

vol correction: 2.5

units: x10³ WBC/uL or x10^9 WBC/L

cells/mm3 or cells/mL = (number of cells counted) x (dilution factor) x (volume correction factor)

Platelet hemacytometer

dilution factor: 100

vol correction: 10

units: plt/mm³

cells/mm3 or cells/mL = (number of cells counted) x (dilution factor) x (volume correction factor)

MCV indicies

MCV (fL) = (Hct% x 10) / RBC

MCH indicies

MCH (pg) = (Hgb x 10) / RBC

MCHC indicies

MCHC (%) = (Hgb x 100) /RBC or (MCH/MCV)x100

Absolute cell counts for WBC

absolute WBC = (% cell type / 100) xWBC

Molality

M= (weight used/molecular weight)/ volume in L

M= moles/L

Normality

N= (weight used/ (molecular weight/valence))/ vol in L

N= M x valence

Equivalent weight = molecular weight / valence

Must use Normality when problem uses: neutralize, react with, or equal

Concentration

C1V1 = C2V2

Mean

Average

sum of values/ number of values

Median- literal middle value

Mode- most frequent value

Standard Deviation

Average distance of an individual value from the mean

square root of (the sum of (value - mean)² )/ n-1

95% confidence interval (CI)

The range of values that are fairly sure of the true value lying within a normal distribution

95% CI = mean plus or minus 2SD

Coefficient of Variation (CV)

CV= SD/mean x100

Sensitivity / True Positive

Sensitivity = TP/(TP+FN)

Specificity / True Negative

Specificity= TN/(TN+FP)

Positive Predictive Value

PPV= TP/(TP+FP)

The probability of the disease when the test result is positive

Negative Predictive Value

NPV= TN/(TN+FN)

The probability of the disease when the test result is negative

C to F

C/ (F-32) = 5/9

Kelvin

C + 273

Kleihaurer-Betke and RhIG dose

FMH (mL) = (# of fetal cells / 2000 cells total) x 5000 mL

5000mL is approx maternal blood volume unless specified

RhIG# = (FMH / 30) +1

Henderson-Hasselbalch

pH = pK + log([HCO3]/(0.03 x pCO2)