ratnakar1811
★

India,
2009-10-15 11:13
(4060 d 14:51 ago)

Posting: # 4358
Views: 4,735

Reference ranges [Study Per­for­mance]

Dear All,

This is with respect to the above mentioned subject, as reference ranges are slightly changed from lab to lab, because of different methods, reagents used and standards used. Also labs change their reference ranges from time to time.

My query is do we really need to mention the lab normal ranges in the protocol or only name of the tests are sufficient? As earlier we used to mention only name of the tests but during one of the regulatory inspection it was suggested to mention reference ranges in the protocol. Now we have mentioned two different lab facilities in the protocol, and both have slightly different normal ranges for some parameters due to which it becomes difficult which reference ranges to be mentioned in the protocol? Because of which there may be chances that one of the subject's value for one of the parameter is absolutely with normal range as per one lab and for other subject the same value may have to be considered as clinically not significant as analysed at other facility which may confuse when reported in the final report?

Your views in this regards will be highly appreciated.

Regards,

Ratnakar

Edit: Category changed. [Helmut]
Helmut
★★★

Vienna, Austria,
2009-10-15 13:33
(4060 d 12:31 ago)

@ ratnakar1811
Posting: # 4361
Views: 3,917

Transformation of lab values

Dear Ratnakar!

» My query is do we really need to mention the lab normal ranges in the protocol or only name of the tests are sufficient?

I haven’t seen reference ranges in any protocol yet.

» […] during one of the regulatory inspection it was suggested to mention reference ranges in the protocol.

Interesting. Which country’s inspector?

» […] slightly different normal ranges for some parameters

Yes, as you also have mentioned it is not uncommon that reference ranges change during the course of a study.

Consider transforming values* to a predefined range
$$R_t=S_L+\frac{R_u-I_L}{I_H-I_L}\left(S_H-S_L \right) \tag{12.5.1}$$where $$\small{R_u}$$ and $$\small{R_t}$$ denote the untransformed and transformed result, $$\small{(I_L,I_H)}$$ and $$\small{(S_L,S_H)}$$ are the investigators’ (lab) and standard (protocol) lower/upper limits of the reference range. In the protocol you may give the standard range and mention the planned transformation. However, if the lab's range don’t change as planned you don’t have to worry because $$\small{{R_t}=R_u}$$.
Example: Standard range 10–300 $$\small{(S_L,S_H)}$$, lab’s range changed to 8–240 $$\small{(I_L,I_H)}$$, measured 9 ($$\small{R_u}$$ within the lab's new range, but outside the old standard range), transformed value 11 ($$\small{R_t}$$ within the old standard range).

For details and an alternative method see Chow & Liu.*

• Chow S-C, Liu H-p. Design and Analysis of Clinical Trials. Concepts and Methodologies. New York: Wiley; 1998. p. 560–2.

Dif-tor heh smusma 🖖
Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
ratnakar1811
★

India,
2009-10-15 14:37
(4060 d 11:27 ago)

@ Helmut
Posting: # 4364
Views: 3,853

Transformation of lab values

Dear HS,
Thanks for your promt reply and guidance! I will come back to you.

Regards,

Ratnakar

Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Helmut]
Helmut
★★★

Vienna, Austria,
2009-10-15 14:46
(4060 d 11:18 ago)

@ ratnakar1811
Posting: # 4365
Views: 3,880

Which country?

Dear Ratnakar!

» I will come back to you.

Yes please - but anwering my question first. Might be useful to all of us!

Dif-tor heh smusma 🖖
Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
ratnakar1811
★

India,
2009-11-30 09:12
(4014 d 15:52 ago)

@ Helmut
Posting: # 4400
Views: 3,729

Which country?

Dear HS,
Sorry for the delay, the inspector was from Singapore.

Regards,

Ratnakar
Helmut
★★★

Vienna, Austria,
2009-11-30 18:23
(4014 d 06:41 ago)

@ ratnakar1811
Posting: # 4401
Views: 3,792

Aha!

Dear Ratnaka!

» […] the inspector was from Singapore.

THX, very interesting!

Dif-tor heh smusma 🖖
Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
kartikpharma
☆

2009-12-03 09:58
(4011 d 15:06 ago)

@ ratnakar1811
Posting: # 4411
Views: 3,694

Reference ranges

Dear Ratnakar,

You have to put ref range in your protocol.

You can find out ref range (By statistical method) from all historical subject screening data.

Regards,

Kartik Patel

Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Helmut]