Sperm selection for ICSI (IMSI and PICSI)

The step they change

In ICSI, one sperm is chosen for each egg. In the words of the UK fertility regulator, the HFEA, “a skilled embryologist (embryo specialist) will inject a single sperm into the egg.” IMSI and PICSI are two ways of making that choice. They are on one page because they change the same step, and the HFEA says the same thing about the safety of each.

IMSI: choosing under very high magnification

The HFEA says “Intracytoplasmic morphologically selected sperm injection (IMSI) is a sperm selection method used in intracytoplasmic sperm injection (ICSI). The technique involves using a microscope to view detailed images of the sperm under very high magnification (over x6000) to select the sperm to inject into an egg.”

PICSI: choosing sperm that bind to hyaluronic acid

The HFEA says “Physiological intracytoplasmic sperm injection (PICSI) is a technique used to select sperm to use in Intracytoplasmic sperm injection (ICSI) treatment. It involves placing sperm with hyaluronic acid (HA), a natural compound found in the body. PICSI identifies sperm that can bind to HA and these sperm are selected for use in treatment.”

Its list of add-ons describes PICSI as “in use for patients having ICSI treatment for male factor infertility”. Whether it is appropriate in a particular case is a clinical decision for the treating doctor. This directory does not make that judgement.

What neither one changes

Neither replaces ICSI. The injection itself, and the rest of the IVF cycle, are the same with or without them. Clinics in this directory whose websites name ICSI itself: 321.

Add-ons, and what the HFEA asks patients to do

The HFEA lists both as treatment add-ons, which it defines as “optional non-essential treatments or tests that may be offered in addition to such proven fertility treatment”. On each page it begins: “For most patients, having a routine cycle of proven fertility treatment is effective without using any treatment add-ons.”

It publishes its own rating of the evidence for IMSI and for PICSI, and this directory links to those pages rather than restating them. It notes: “Our ratings do not tell you how much that treatment add-on improves your chances of having a baby – please discuss this with your clinic.”

Its advice to patients: “If a treatment add-on is offered, you should question why it is being offered and ask if it may be of benefit for you specifically.” And “Your clinic should provide you with the evidence of effectiveness of any treatment they offer you.”

On cost, without naming a figure: “If you are paying for your own treatment, you may want to think about whether it might be better to pay for multiple cycles of IVF or IUI, rather than spending large sums of money on a single treatment cycle with treatment add-ons that haven't been proven to be effective.”

What the regulator says about risks

On IMSI, the HFEA states: “IMSI is a non-invasive test performed on a semen sample as an additional step in the ICSI process. The risks associated with the use of ICSI also apply to IMSI. However, IMSI does not carry any additional known risks for the person undergoing fertility treatment or the child born as a result of fertility treatment.”

On PICSI: “PICSI is a non-invasive test performed on a semen sample as an additional step in the ICSI process. The risks associated with the use of ICSI also apply to PICSI.”

For both, it says “If you have any questions about the safety and risks, your clinic will be able to discuss whether a treatment add-on would be safe for you to use considering your specific medical history and circumstances.” The ICSI risks it refers to are quoted in full on the ICSI page.

Questions

Why are IMSI and PICSI on one page?

Because both are ways of choosing the sperm for ICSI, and neither is a treatment on its own. This directory used to give each its own page; both old addresses now lead here.

Are IMSI and PICSI the same?

No. IMSI chooses sperm by looking at them under very high magnification; PICSI chooses sperm that “can bind to HA”, hyaluronic acid.

Is either one a replacement for ICSI?

No. The HFEA calls IMSI “a sperm selection method used in intracytoplasmic sperm injection (ICSI).” PICSI is also used within ICSI.

Do they add risk?

The HFEA says “IMSI does not carry any additional known risks for the person undergoing fertility treatment or the child born as a result of fertility treatment.” For PICSI it says “The risks associated with the use of ICSI also apply to PICSI.”

Are they charged separately?

This directory holds no prices. Add-ons are often priced separately; ask each clinic for an itemised written quote.

Sources

• HFEA, Intracytoplasmic sperm injection (ICSI), read 25 September 2026.
• HFEA, Intracytoplasmic morphologic sperm injection (IMSI), read 25 September 2026.
• HFEA, Physiological intracytoplasmic sperm injection (PICSI), read 25 September 2026.
• HFEA, Treatment add-ons, read 25 September 2026.
• The Assisted Reproductive Technology (Regulation) Rules, 2022, G.S.R. 419(E), 7 June 2022, para 10.1 (not changed by the Amendment Rules, 2026, G.S.R. 491(E)), read 25 September 2026.
• Clinic data: each clinic's own website, as read by this directory; registry level from the National ART & Surrogacy Registry extract.