MLT ,Water & Sterility Testing Images

MVD = Endotoxin limit X Concentration of the product

Lysate sensitivity (λ).

Not more than 145 Endotoxin units/mg X 0.68 mg/mL

= ------------------------------------------------------------------- 0.03 EU/mL

= 3286.66 Round off to 3072

Where:

0.03 EU/mL is Lysate label claim sensitivity.

Concentration of the sample 0.68 mg/mL.

Not more than 145 Endotoxin units/mg is the Endotoxin limit of the product.

S.No.	Quantity of sample	Quantity of LRW	Sample dilution	MVD
1	2 mL of sample	4 mL	1:3	MVD/1024
2	1 mL of 1:3	1 mL	1:6	MVD/512
3	1 mL of 1:6	1 mL	1:12	MVD/256
4	1 mL of 1:12	1 mL	1:24	MVD/128
5	1 mL of 1:24	1 mL	1:48	MVD/64
6	1 mL of 1:48	1 mL	1:96	MVD/32
7	1 mL of 1:96	1 mL	1:192	MVD/16
8	1 mL of 1:192	1 mL	1:384	MVD/8
9	1 mL of 1:384	1 mL	1:768	MVD/4
10	1 mL of 1:768	1 mL	1:1536	MVD/2
11	1 mL of 1:1536	1 mL	1:3072	MVD

Sure. The 4 mL LRW in your first step comes from making a 1:3 dilution.

You have 2 mL of sample.

For a 1:3 dilution, the sample should be 1 part of the final 3 parts.

So:
$\text{Total volume} = 2\text{ mL} \times 3 = 6\text{ mL}$
You already have 2 mL sample, so the amount of LRW needed is:
$6 - 2 = \boxed{4\text{ mL LRW}}$
Therefore:

2 mL sample + 4 mL LRW = 6 mL total

And:
$\frac{2}{6}=\frac{1}{3}$
So the final dilution is 1:3.

Simple formula

$\boxed{\text{LRW required}=(\text{desired dilution} \times \text{sample volume})-\text{sample volume}}$
For your example:
$(3\times2)-2=4\text{ mL}$
That's why they use 4 mL LRW

Step 1: Ask: how much dilution do we need?

Current dilution = 100
Required dilution = 256

So:

$256 \div 100 = 2.56$

That means the 1:100 solution needs to be diluted another 2.56 times.

Step 2: We decide to take 1 mL

Suppose we take:

1 mL of the 1:100 solution

We want this 1 mL to become a 2.56-fold dilution.

Therefore, the final volume must be 2.56 mL.

So:

$1\text{ mL sample} + ?\text{ mL LRW}=2.56\text{ mL}$

To find the LRW:

$2.56-1.00=\boxed{1.56\text{ mL}}$

That's where 1.56 mL LRW comes from.

Think of it like this


1.00 mL 1:100 solution
       +
1.56 mL LRW
       ↓
2.56 mL total
       ↓
additional dilution = 2.56
       ↓
100 × 2.56
       ↓
1:256

So 1.56 mL is not a random number.

It is simply:

Required final volume − sample volume

2.56 mL − 1.00 mL = 1.56 mL LRW

Why do we choose 1 mL?

Because 1 mL is a convenient amount to work with. You could theoretically use another amount, but the LRW amount would change proportionally.

For example, using 2 mL of the 1:100 dilution:

$2\times2.56=5.12\text{ mL final volume}$

LRW needed:

$5.12-2=3.12\text{ mL}$

So 2 mL sample + 3.12 mL LRW also gives 1:256 overall.

The key formula to remember is:

LRW to add = (required final dilution ÷ current dilution × sample volume) − sample volume

For your case:

$(256 \div 100 \times 1) - 1 = 2.56 - 1 = 1.56 mL LRW$

Column	What it means	What you should write
Component / Function	What part, process, or activity are you analyzing?	Name the component and describe what it is supposed to do.
Potential Failure Mode	How could it fail?	Describe the specific way the component/process might not work as intended.
Potential Failure Effect or Consequence	What happens if it fails?	Describe the impact on the user, product, process, safety, quality, etc.
Contributory Factors / Failure Causes	Why could the failure happen?	List the possible causes or contributing factors.
Current Controls	What is already being done to prevent/detect the failure?	Inspections, alarms, testing, procedures, training, maintenance, checks, etc.
Severity (S)	How serious is the effect?	Usually rated 1–10, where 1 = negligible and 10 = very serious/catastrophic.
Occurrence (O)	How often is the failure likely to happen?	Usually 1–10, where 1 = very unlikely and 10 = frequent.
Detection (D)	How likely are you to detect the failure before it causes harm?	Usually 1–10, where 1 = very easy to detect and 10 = very difficult to detect.
RPN (S × O × D)	Overall risk priority number	Multiply the three ratings: RPN = S × O × D.
Risk Acceptance (Yes / No)	Is the calculated risk acceptable?	Write Yes if the risk is within your organization's acceptable limit; otherwise No.
Recommended Action(s)	What should be done to reduce the risk?	Improvements such as additional controls, redesign, testing, training, preventive maintenance, or monitoring.