FORMULAS

Question 1

Sodium Citrate Con. Correction

Answer 1

(1.8 x 10^-3) (100-H)(V) = C

Use only if the hct is >55

Question 2

Routine Light Microscopy Method

Answer 2

% = No. of retics /1000RBCs x 100

Question 3

PT Formula (INR)

Answer 3

(patients PT/Mean Normal PT)^ISI

Question 4

Calibrated Miller Disc Method

Answer 4

% = total retics in square A / (total RBCs in Square B x 9) x100

Question 5

Absolute Retic count

Answer 5

AR= [no of retics% x RBC count (x10^12/L)] / 100 x 1000

may mal

Question 6

Corrected Retic count

Answer 6

CRC = retics (%) x [HCT (L/L) / 0.45L/L

Question 6

Reference range for ARC

Answer 6

20 - 115 x 10^9/L

Question 7

Retic Production Index

Answer 7

Corrected Retic count / Maturation Time in the Peripheral Blood

Question 7

Hgb

Answer 7

RBC ct x 3

Hct = Hgb x 3

Question 8

MCH

Answer 8

Hgb / RBC x10

Question 8

MCV

Answer 8

Hct / RBC x 10

Question 9

MCHC

Answer 9

Hgb / Hct x 100

Question 10

Formula for RBC count rules

Answer 10

Ave cell x DF / ACF x depth facy

Question 11

Absolute count of each cell for Absolute WBC count

Answer 11

WBC diff. count (in dec) x Total WBC count (x10^9)

Question 12

Corrected WBC Ct

Answer 12

CR WBC ct = (uncontrolled WBc x100) / (nucleated rbcs + 100)

Question 13

Formula for platelet count (Rees and Ecker)

Answer 13

(total cells counted x df) / (ACF x depth factor)

ACF = 10(0.04) = .4

Question 14

Platelet formula (Unopette)

Answer 14

(total cells counted x df) / (ACF x depth factor)

ACF = 10(0.04) = .4

Question 15

WBC ct estimate if 40x magnification is used

Answer 15

Average WBC x 2000

Question 16

WBC ct estimate if 50x magnification is used

Answer 16

Average WBC x 3000

Question 17

Platelet ct. estimate

Answer 17

Average platelet per field x 20,000

Question 18

Platelet ct. estimate (patient has erythrocytosis or increased Hct value)

Answer 18

Average platelets per field x rb ctc / 200 RBCs

Question 19

Computation for Cyanmethemoglobin methed (beer’s)

Answer 19

(OD of sample/OD of standard) x ( conc. of standard (mg/dL)/100 mg/g) x 251

5mL of Drabkin’s = 1:251
6mL = 1:301

C test = (C standard x A test)/A standard

Question 20

Corrected Hgb

Answer 20

Hgb - [plasma Hgb x (1-Hct)]

Question 21

Retic inx / RPI / CRC

Answer 21

Absolute Retic count / Maturation correction

Question 22

Absolute rectic count

Answer 22

% of retic x (px Hct / Normal hct)

Question 23

ZSR

Answer 23

hct % / zeta crit x 100