CFU/ML

> 100,000 or 10^5 CFU/ML = infection

<101^3 CFU= no infection

0.01 Loop CFU X 100

0.001 LOOP CFU X 1000

MCV

HCT/RBC X 10

(80-100fl)

MCH

HGB/RBC X 10

(27-31PG) 

MCHC

HGB/HCT X 100

(32-36%) 

WBC Correction for NRBC 

Automated WBC x 100/(NRBC +100) 

Hemocytometer Count 

# of cells mm³= # of cells x depth factor x dilution factor/area counted 

Retics

# of retics / 1000 x 100

Corrected Reticulocyte Count

calculated retic x patient HCT/normal HCT (45%) 

Lap Score 

reactivity/score x cells counted= lap score 

add all the scores to get your final total 

Range: 20-100

Corrected Creatinine Clearance 

urine creatinine x volume 

--------------------------

plasma creatinine 

or 

uxv

------

p

Creatinine Clearance with collection time and BSA  

conversion:

Collection time x 60

 time/urine volume  = new urine volume

Formula: 

U X V/P (1.73/BSA) 

Temperature 

F⁰= (1.8 x c^o) + 32

       C⁰= (F⁰ - 32) / 1.8 or 5/9

Rhogam/Rhig

round up and add 1 vial

% fetal cells = # fetal cells/100 x 100 

vials of rhogram = % fetal cells / 30 x 50 (add 1) 

Beer's LAW

A=abc

C unknown = Abs u/ Abs S x C STD

Recognize:

A= 2-log%T

Simple Dilutions 

Sample volume

SV = SV / TV

Diluent volume

DV = TV - SV

Total volume

TV = SV + DV 

Changing Concentrations

V1C1 = V2C2

Molarity 

M = #of grams/ gmw / V (L) 

Normality 

N = # of grams/GEW/ V (L)

Coefficient of Variation (CV) 

% CV = SD/mean x 100

Osmolality

Cal Osmo

2NA + GLU/18 + BUN/2.8

round to the nearest whole number 

Friewald Calculation (lipids)

LDL = T CHOL - (HDL + VLDL)

To get VLDL: 

Trigly/5

LDL < 100 mg/dl

Triglycerides < 150 mg/dl

T CHOL < 200 mg/dl

Anion Gap

(NA²⁺ + k^t) - (CL^- + Hc0^-₃)

Range:

10 - 20

Henderson-Hasselbach equation 

pH= pKa + log HcO3/H2co3 

Screening for compatible units 

100% - frequency of antigen 

Multiple antibodies: 

must figure out % frequency of each antigen x frequency antigen 1 x frequency antigen 2